Term
atom-intro
a) What is a proton?
b) What is an electron? |
|
Definition
a) A proton p+ is a particle that
1) has a positive electric charge of +1e [e the electric charge of 1 electron]
2) is very small (radius around: 10-15m)
3) has very little mass (around 10-24g)
b) An electron e- is a particle that
1) has a negative electric charge of -1e [e the electric charge of 1 electron]
2) is very, very small (radius around: 10-18m)
3) has very, very little mass (around 10-27g) [1 p+ has the mass of 1,836 e-]
|
|
electric
charge
|
mass g
|
radius m
|
|
proton
|
+1e
|
1.6726*10-24
|
0.9*10-15
|
|
electron
|
-1e
|
0.9109*10−27
|
10-18
|
|
|
|
Term
What is a meter [m]?
What is a gram [g]
Write 10-15m in decimals?
Write 10-24g in decimals? |
|
Definition
What is a meter [m]? unit for length: 1 inch = 0.0254 m
What is a gram [g]? unit for mass: 1 lbs = 453.6 g
What does 10-15m mean? 1/000,000,000,000,001 m
What does 10-24g mean? 1/000,000,000,000,000,000,000,001 g
n = 1,2,3 … 100 positive integer
a) 10n is the number 1 with n zeros : 103 = 1,000
b) 10-n is the number 1 divided by 10n: 10-3= 1/103= 1/1,000 =0.001
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|
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Term
atom-intro
a) Describe how 1 proton and 1 electron act together on earth!
b) What is the name of a unit consisting of 1 proton and 1 electron?
http://www.lookchem.com/Periodic-Table/Hydrogen/ |
|
Definition
a) Describe how 1 proton and 1 electron act together on earth!
imagine a sphere with the proton p+ at the center called the nucleus and
the electron e- zipping very fast around this nucleus.
The whole thing looks like a very small ball (radius: 0.5*10-10m)
2) name:
This combination of 1 proton and 1 electron is called a Hydrogen atom.
A Hydrogen atom is the smallest unit of the element Hydrogen (symbol H).
There are 118 known elements each having different number of protons (1,2,...,118)
Elements combine through chemical reactions
to different kind of matters making up our universe. |
|
|
Term
atom-intro
Hydrogen-1 & Helium-4
Compare the two elements
a) symbol
b) atom
c) mass relative to Hydrogen
d) state (solid, gas, liquid)
e) chemical reactivity
http://chemical-elements.findthedata.org/compare/40-42/Helium-vs-Hydrogen |
|
Definition
|
|
Hydrogen
|
Helium
|
|
a) symbol
|
H
|
He
|
|
b) atom - #p+
|
1
|
2
|
|
#n0 *
|
0
|
2
|
|
#e- **
|
1
|
2
|
|
c) mass rel. to H
|
1
|
4
|
|
d) state (standard)
|
gas
|
gas
|
|
e) chem. reactivity
|
strong
explosion!
|
none
inert
|
* mostly occurring naturally ** neutral atom
mass of proton 1.6726*10-24g
mass of neutron 1.6749*10-24g
mass of electron 0.0009*10-24g (1840 e's have the mass of 1 p) |
|
|
Term
atom-intro
Gold
a) What is the symbol of the element Gold?
b) How many protons, neutrons and electrons are in a neutral Gold atom?
c) How and when was a Gold atom created?
http://www.chemicalelements.com/elements/au.html
http://en.wikipedia.org/wiki/Supernova
http://en.wikipedia.org/wiki/Supernova_nucleosynthesis
http://www.answers.com/topic/supernova |
|
Definition
a) symbol of Gold: Au
b) protons, neutrons, electrons in a neutral Au atom:
#p+= 79, #n0 = 118, #e- = 79 (for neutral atom: #p+=#e-)
c) method to create a Gold atom: nucleosynthesis in supernovae.
To create an Au atom, 79 p+ and 118 n0 are fused into one nucleus.
This requires a huge amount of energy
that is found in supernovas (violent explosions of huge stars)
[comparison to core of the sun:
not enough energy to fuse more than 2 protons and 2 neutrons ( = Helium atom)]
Supernova: collapse of a massive star when its nuclear fuel is exhausted
releasing huge amount of energy.
|
|
|
Term
Forces in an atom
a) What is a force?
b) Which forces are effective in an atom?
http://abyss.uoregon.edu/~js/ast122/lectures/lec06.html |
|
Definition
a) What is a force? A force is a push or a pull on an object (object in atom: p+,n+,e-)
b) Which forces are effective in an atom?
[image] |
|
|
Term
atom-intro
European alchemists in the Middle Ages tried
to convert atoms of the element Lead Pb
into atoms of the element Gold Au.
a) How to convert a Lead atom into a Gold atom?
b) Why where the alchemists unsuccessful?
http://chemistry.about.com/cs/generalchemistry/a/aa050601a.htm
http://www.chemicalelements.com/elements/pb.html
http://www.chemicalelements.com/elements/au.htm
|
|
Definition
|
|
Lead
|
Gold
|
|
|
symbol
|
Pb
|
Au
|
* mostly occurring naturally
** neutral atom #p+=#n0
|
|
atom - #p+
|
82
|
79
|
|
#n0 *
|
125
|
118
|
|
#e- **
|
82
|
79
|
a) How to convert a Pb atom into an Au atom
1) To change one element into another:
Change the # of protons in the nucleus of the atom
To convert 1 Pb atom into a1 Au atom: take 3 protons out of the nucleus
2) To make the atom of the new element stable (not fall apart),
Adjust the number of neutrons (glue for protons, the right number necessary)
take 7 neutrons out of the nucleus
3) To make the atom of the new element neutral (no electric charge: #p+=#e-)
Make the number of protons (positive charge) equal to the number of electrons
take 2 electrons out of the atom (electrons are not in the nucleus)
b) Why where the alchemists unsuccessful?
Chemists (formerly called Alchemists) cannot change the nucleus of a stable atom.
Modern Nuclear physicists can.
|
|
|
Term
atom - basics
a) What is a proton?
b) What do protons do? |
|
Definition
a) What is a proton? (abbreviation: p+ or p)
A proton is a particle in the nucleus of an atom.
with a positive electric charge of +1 [e].
b) What do protons do?
The number of protons in an atom makes the element.
Change the number of protons and you change the element.
Atomic number Z = #p
Elements are the basic building blocks of matter.
|
Name
|
Sym
-bol
|
atomic
number
Z = #p
|
electric
charge
nucleus
|
Name
|
Sym
-bol
|
atomic
number
Z = #p
|
electric
charge
nucleus
|
|
Hydrogen
|
H
|
1
|
+1[e]
|
Carbon
|
C
|
6
|
+6[e]
|
|
Helium
|
He
|
2
|
+2[e]
|
Nitrogen
|
N
|
7
|
+7[e]
|
|
Lithium
|
Li
|
3
|
+3[e]
|
Oxygen
|
O
|
8
|
+8[e]
|
|
Beryllium
|
Be
|
4
|
+4[e]
|
Fluroine
|
F
|
9
|
+9[e]
|
|
Boron
|
B
|
5
|
+5[e]
|
Neon
|
Ne
|
10
|
+10[e]
|
* also called electromagnetic charge [1 [e] =1.602 * 10-19 [C]
Definition: 1 Coulomb [C] is the electric charge of 6.2415*1018 electrons |
|
|
Term
atom - basics
a) What is a neutron?
b) What do neutrons do?
http://aether.lbl.gov/elements/stellar/strong/strong.html |
|
Definition
a) What is a neutron? (abbreviation n0)
A neutron is a particle in the nucleus of an atom
with no electric charge .
b) What do neutrons do?
neutrons help to glue the positively charged protons together.
[image]
|
|
|
Term
atom - basics
a) What is an electron?
b) What are electrons responsible for?
|
|
Definition
a) What is an electron? (abbreviation e-)
An electron is a subatomic particle
each with a negative electric charge of -1 [e] *
zipping around the nucleus of an atom.
* also called electromagnetic charge 1 [e] =1.602 * 10-19[C]
Definition: 1 Coulomb [C] is the electric charge of 6.2415*1018 electrons
b) What are electrons responsible for?
electrons e- are responsible for
1) chemical reactions
2) electric charge of an atom = #p+ - #e-
a) neutral atom: #p+ - #e- = 0
b) Ion: #p+ - #e- <> 0
3) color of matter: electrons interacting with visible light
4) electricity (flow of electrons)
5) electronics (semiconductors) and more
The mighty little electron!
|
|
|
Term
atom - basics
a) What is an atom?
b) What are subatomic particles?
http://www.epa.gov/rpdweb00/understand/atom.html
http://chemwiki.ucdavis.edu/Physical_Chemistry/Atomic_Theory/Sub-Atomic_Particles |
|
Definition
a) What is an atom?
Atoms are the fundamental building blocks of matters
consisting of protons, neutrons and electrons.
b) What are subatomic particles?
Subatomic particles are particles within an atom.
There are three kind of suabtomic particles
1) protons: positive electric charge (+) in the nucleus
2) neutrons: none (0) in the nucleus
3) electrons: negative electric charge (-) around the nucleus
|
|
|
Term
atom - basics
Where do you find
1) protons
2) neutrons
3) electrons
in an atom?
|
|
Definition
You find protons and neutrons in the nucleus,
electrons are zipping around the nucleus.
[image]
The nucleus is at the center of the atom.
|
|
|
Term
atom - basics
What are the electric charges of the subatomic particles?
http://www.physics.sjsu.edu/becker/physics51/elec_charge.htm
http://nohiggs.wordpress.com/2010/06/28/more-about-magnetic-monopoles/ |
|
Definition
subatomic particle electric charge* of each particle
1) protons p+: positive +1 [e]
2) neutrons n0: none 0 [e]
3) electrons e-: negative -1 [e]
* also called electromagnetic charge [1 e =1.602 * 10-19 [C]
Definition: 1 Coulomb [C] is the electric charge of 6.2415*1018 electrons
Study how magnets attract and repel each other.
+ - attract
a) -- or b)++ repell each other
magnets have - poles and + poles (magnetic dipole)
p's (+) and e's (-) have only 1 pole (magnetic monopole) |
|
|
Term
atom - basics
Can one split an atom? |
|
Definition
Yes, you can split an atom into
the following subatomic particles:
electric charge where
1) protons p+ +1 [e] in nucleus
2) neutrons n0 0 [e] in nucleus
3) electrons e- -1 [e] around nucleus
|
|
|
Term
summary (advanced)
atom - basics
Subatomic Particles
a) electric charge
b) location
c) mass
d) radius
http://en.wikipedia.org/wiki/Elementary_charge |
|
Definition
Subatomic particles: proton p, neutron n, electron e
a) electric charge: p+:+1 n0: 0 e-:-1
b) location: p+ & n0: in nucleus ; e-: around nucleus
c) mass (about) p+, n0: 1.6*10-24g [n0 slightly more mass than p+]
e-: 1 *10-28g [1840 e's the mass of 1 proton]
g) radius in meter [m]: p+ & n0: 10-15m e-: 10-18m
|
|
electric
charge [e]
|
location
|
mass [g]
|
radius [m]
|
|
proton
|
+1
|
nucleus
|
1.6726*10-24
|
0.9*10-15
|
|
neutron
|
0
|
nucleus
|
1.6749×10−24
|
1.1*10-15
|
|
electron
|
-1
|
around nucleus
|
9.1094×10−28
|
10-18
|
charge of a 1 proton 1e = 1.602×10−19C [C Coulomb]
|
|
|
Term
elements
What is a chemical element?
|
|
Definition
A chemical element is a substance (matter)
with all their smallest units (called atoms)
having the same number of protons.
Example: All atoms of the element Sodium Na have 11 protons.
A proton (+) is a positively charged subatomic particle in the nucleus of an atom.
2 other subatomic particles are neutrons (0) and electrons (-).
The number of neutrons and electrons do not change the identity of the element!
Other definition: An element is a substance
that cannot be further resolved into simpler substances by chemical means. |
|
|
Term
elements
Where are all elements listed?
http://www.ptable.com/
http://www.webelements.com/ |
|
Definition
All elements are listed in the
Periodic Table of the Elements (PTE)
ordered by increasing number of protons.
There are 118 elements
98 naturally occurring
20 man made in Laboratories
Below are the first 10 elements of the PTE. The letter is the symbol of the element, the number is the number of protons of the element, called the atomic number Z. H: Hydrogen Z = 1 (1 proton)
[image]
|
|
|
Term
elements
How many elements are known today?
Name the first ten!
http://www.aip.org/history/curie/periodic.htm
|
|
Definition
118 elements are known (more may be discovered)
98 elements are found in nature
(from 1 Hydrogen H to 98 Californium Cf)
20 were created in laboratories (unstable)
(from 99 Einsteinium Eu to 119 118 Ununoctium Uuo)
First 10 elements of the Periodic Table of the Elements
1 Hydrogen H 2 Helium He
3 Lithium Li 4 Beryllium 5 Boron B 6 Carbon C 7 Nitrogen N 8 Oxygen O 9 Fluorine F 10 Neon Ne |
|
|
Term
elements
Which elements
and how much* of each
is in your body?
* as percentage of mass
How old are the atoms of the elements in your body? |
|
Definition
CHNOPS + Ca
Carbon Hydrogen Nitrogen
Oxygen Phosphorus Sulfur
[% of total mass]
Oxygen O 65% Nitrogen N 3%
Carbon C 18% Calcium Ca 1.4%
Hydrogen H 10% Phosphorus P 1.1%
Sulfur S 0.25%
Under 1%: Mn, Na,Fe, Mg, Cu, Cl, I, K
Most atoms in your body is probably at least 4.5 billion years old.
[4,500,000,000 years = 4.5*109 years] |
|
|
Term
elements
Which elements and how much of each* is in the earth?
* as % of total mass
How old is the earth? |
|
Definition
Oxygen O 63% of total mass of the earth (5.972*1027 g)
Silicon S 21%
Aluminum Al 6%
less than 3%: Sodium Na Calcium Ca Iron Fe
Magnesium Mg Potassium K
Our solar system including our earth is 4.54 billion years old.
|
|
|
Term
elements
Is water an element? |
|
Definition
Water H2O not an element,
because it does not contain only atoms with the same number of protons: Hydrogen H 1 proton
Oxygen O 8 protons,
Water is a compound that can be broken down into atoms of 2 different elements (Hydrogen and Oxygen)
All atoms of an element (such as Oxygen O) have the same number of protons.
proton: subatomic particle with a positive electric charge in the nucleus of an atom |
|
|
Term
atom
What electric charge can an atom have? |
|
Definition
An atom can have a neutral (0), positive (+) or negative (-) electric charge depending on its number of protons and electrons.
Each proton has a charge of +1 [e]
Each electron has a charge of -1 [e].
Therefore: electric charge of atom = #p+ - #e-
Atomic Number Z = #p (number of protons in atom)
Electron Number E = #e- (number of electrons in atom)
An atom may have
1) no electric charge: Z - E = 0 if Z = E
If an atom has the same number of protons and electrons.
it is called a neutral atom
example: neutral Na atom: Z = 11 E = 11
2) an electric charge: Z - E <> 0 if Z <> E
An atom with unequal number of protons and electrons
is called an ion
a) positive charge: Z - E > 0 if Z > E
This atom is called a cation [cat-ion]. [Na+, Ca2+]
b) negative charge: Z - E < 0 if Z < E
This atom is called an anion [an-ion]. [Cl-, O2-]
|
|
|
Term
exercise
atom
|
atom
|
|
Z
|
E
|
electric charge [e]
|
Symbol
|
|
1
|
1
|
|
|
|
1
|
0
|
|
|
|
11
|
10
|
|
|
|
17
|
18
|
|
|
|
12
|
10
|
|
|
|
16
|
18
|
|
|
|
|
Definition
|
atom
|
|
Z
|
E
|
electric charge [e]
|
Symbol +
charge
|
|
1
|
1
|
0
|
H
|
|
1
|
0
|
+1
|
H+
|
|
11
|
10
|
+1
|
Na+
|
|
17
|
18
|
-1
|
Cl-
|
|
12
|
10
|
+2
|
Mg2+
|
|
16
|
18
|
-2
|
S2-
|
|
|
|
Term
atom -proton
In what order are the elements shown
in Periodic Table of Elements (PTE)? |
|
Definition
The Periodic Table orders elements
by the number of protons in the nucleus of its atom.
This is because the number of protons determines the identity of an element.
The atomic number Z of an element gives the number of its protons
Z = #p
The first element is Hydrogen [H] with 1 proton,
currently the last ist Ununoctium [Uuo], a man-made element, with 118 protons.
Element Protons Element Protons
H 1H 1 Na 11Na 11 ZX : #pSymbol
He 2He 2 Cf 98Cf 98
Uuo 118Uu0 118
|
|
|
Term
atom -proton
In an atom, where do you find all the protons? |
|
Definition
All the protons of an atom are in its nucleus.
Each protons has an electric charge of +1.
If an atom has 8 protons (Oxygen O),
the electric charge of its nucleus is +8.
Important:
If there are more than 1 proton in a nucleus
they need neutrons for stability.
|
|
|
Term
exercise
atom -proton
What is the electric charge of an atom
with only 1 proton (nothing else)? |
|
Definition
An atom
with only 1 proton (and nothing else)
has a positive charge of +1 [e]
(that is the same charge as the proton)
An atom with only 1 proton is called
a Hydrogen cation and written as H+. |
|
|
Term
exercise
atom -proton
Changing the number protons in a nucleus, what happens? |
|
Definition
Changing the number of protons
creates the atom of a different element.
1 proton: Hydrogen H 6 protons: Carbon C
2 protons: Helium He 7 protons: Nitrogen N
3 protons: Lithium Li 8 protons: Oxygen O
4 protons: Beryllium Be 9 protons: Fluorine F
5 protons: Boron B 10 protons: Neon Ne
|
|
|
Term
atom -proton
What is the atomic number Z of an element?
http://education.jlab.org/itselemental/index.html
|
|
Definition
The atomic number Z states
the number of protons in the atom.
Z = # p
Therefore, Z tells you of what element the atom is
(same info as symbol)
For instance: H has 1 proton, for H Z=1
Na has 11 protons, for Na Z=11
In the Periodic Table of the Elements you find the atomic number Z above the symbol of the element
(from 1 to 118)
Sometimes Z is written as a subscript before the symbol of the element: 1H; 2He, 3Li, 98Cf
or zX (where X is any symbol of the element)
|
|
|
Term
atom -proton
Name the elements with up to 10 protons? |
|
Definition
H He
LI Be B C N O F Ne
1 Hydrogen H or 1H 6 Carbon C 6C
2 Helium He or 2He 7 Nitrogen N 7N
3 Lithium Li or 3Li 8 Oxygen O 8O
4 Berrillium Be or 4Be 9 Fluorine F 9F
5 Boron B or 5B 10 Neon Ne 10Ne
|
|
|
Term
atom -proton
How to memorize the first 10 elements in the Periodic Table? |
|
Definition
Build a phrase with one word for each element
H He LI Be B C N O F Ne
Andy
Hi he likes being at basketball court ‘nd offer free Neon.
Eckart
Hi, He Likes Best British Columbia North Of Frosty Nebraska!
|
|
|
Term
exercise
atom -proton
How many protons are in
a) O
b) C
c) Li
d) He
e) Ne
f) B ? |
|
Definition
a) O 8 protons
b) C 6
c) Li 3
d) He 2
e) Ne 10
f) B 5 |
|
|
Term
atom - neutron
a) What is a neutron?
b) What does it do for the atom? |
|
Definition
a) What is a neutron?
A neutron is a subatomic particle with no electric charge
located in the nucleus of an atom.
b) What does it do for the atom?
Neutrons make the nucleus stable by serving as glue for protons,
but only if they are present in the right number.
For instance: Oxygen O has 8 protons and is stable with 8,9 or 10 neutrons, but not with less or more.
Without neutrons, two or more protons with their positive charge without neutrons would repel each other making the nucleus unstable. |
|
|
Term
atom - neutron
How much mass (material, stuff) is in a neutron compared to a proton? |
|
Definition
A neutron has a slightly larger mass
(material) than a proton (+0.14%)
mass % of p mass
neutron: 1.6749286 * 10-24 [g] 100.13784
proton: 1.6726231 * 10-24 [g] 100.00000
electron: 0.0009109 * 10-24 [g] 0.055% (1836 electrons have the same mass as 1 proton)
|
|
|
Term
atom - neutron
My S-Machine lets you shrink yourself
by 1/1000 with a click.
The radius of a neutron is 1.1 *10-15m!
How often do you have to click to shrink yourself to the size of a neutron? |
|
Definition
The radius of a neutron is 1.1*10-15 meters.
You want to shrink yourself to about double that height.
Your height is 5 feet.
That is 1.5 meters (m)
No.clicks your height (after clicks)
1 1.5*10-3m
2 1.5*10-6m
3 1.5*10-9m
4 1.5*10-12m
5 1.5*10-15m
Now you are a little bit shorter than a neutron. |
|
|
Term
atom - neutron
a) When you build an atom, where do the neutrons go?
b) What are nucleoids? |
|
Definition
a) Neutrons belong into the nucleus,
where they help to glue the protons together.
b) Protons and neutrons together
are called nucleoids.
[image] |
|
|
Term
atom - neutron
Does an atom with only 1 proton need a neutron? |
|
Definition
No,
an atom with 1 proton (that is the atom of Hydrogen H)
does not need a neutron,
but it may have 1neutron.
However, if an atom has more than 1 proton,
it must have neutrons,
otherwise the protons could not be glued together in the nucleus.
|
|
|
Term
atom - neutron
How many neutrons does an atom need to be stable? |
|
Definition
To be stable,
an atom needs just the right number of neutrons
(not too few, not too many).
An unstable atom changes naturally into the atom of another element.
For instance, all Hydrogen atoms have 1 proton.
Hydrogen atoms with 0 or 1 neutron are stable.
Hydrogen atoms with 2 neutrons are unstable,
they change into Helium atoms. |
|
|
Term
exercise
atom - neutron
What number of neutrons stabilizes an Oxygen atom? |
|
Definition
8, 9 or 10 neutrons can stabilize
the nucleus of the Oxygen atoms with its 8 protons.
Atoms of the same element with different numbers of neutrons are called isotopes.
Use "Build an Atom" to find out.
http://phet.colorado.edu/en/simulation/build-an-atom
|
|
|
Term
atom - neutron
What number of neutrons always makes
a stable atom for the 10 elements? |
|
Definition
All of the first 10 elements have a stable nucleus, if
number of neutrons = number of protons +1
N = Z + 1
#n* = #p + 1
* for a stable atom of the first 10 elements of the PTE:
H,He,Li,Be,B,C,N,O,F,Ne
Example:
Oxygen with 6 protons in its nucleus
is stable with 7 neutrons |
|
|
Term
atom - neutron
What number of neutrons stabilizes each atom of the 10 elements? |
|
Definition
neutrons for stability
N=#n0
1 H 0 or 1 less
2 He 1 or 2 or
3 Li 3 or 4 more
4 Be 5 unstable!
5 B 5 or 6
6 C 6 or 7
7 N 7 or 8
8 O 8,9 or 10
9 F 10
10 Ne 10, 11 or 12 |
|
|
Term
atom - neutron
What do you call the atoms of the same element
with different number of neutrons?
|
|
Definition
Isotopes is the name for atoms of an element
that has different number of neutrons
( #n0 different, but of course #p+ the same)
atomic number Z = #p+ the same for all isotopes of the same element
mass number A = Z + N #p+ + #n0 different " "
Example: All Carbon (C) atoms have 6 protons (Z =6)
Nearly all Carbon atoms (98.93%) have 6 neutrons (N=6) ; mass number A= 12: Carbon-12 or C-12)
but some Carbon atoms ( 1.07%) have 7 neutrons (N=7) ; mass number A= 13: Carbon-13 or C-13)
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Term
atom - neutron
What are Isotopes?
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Definition
Isotopes
are variants of the same element (Z same)
differing by the number of neutrons (A different)
example: Hydrogen has 2 naturally occurring Isotopes
H-1 Z=1; N=0; 99.9885% atomic number Z = #p
H-2 Z=1; N=1; 0.0115% mass number A = Z+N=#p + #n
Of course all isotopes of an element
have the same number of protons (atomic number Z the same)
because the number of protons makes the element.
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Term
atom - neutron
a) Which are the stable isotopes of Hydrogen?
b) Is there an unstable isotope of Hydrogen H? |
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Definition
a) stable Isotopes of Hydrogen
1) H-1 or 1H: Z=1, N=0
2) H-2 or 2H: Z=1, N=1 (Deuterium D)
b) unstable Isotope of Hydrogen
H-3 or 3H: Z=1, N=2 (Tritium T)
(unstable: 3H cannot remain as it is, it decays into He)
The number with H [H-3 or 3H]
is the sum of the number of protons and neutrons.
This number is called the mass number A:
A = Z + N
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Term
atom - neutron
a) How do the isotopes of an element differ?
b) What is the same for these isotopes? |
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Definition
a) How do the isotopes of an element differ?
The atoms of isotopes of an element
have different number of neutrons in their nucleus.
b) What is the same for these isotopes?
All Isotopes of the same element have the same number of
1) protons
2) electrons (for neutral atoms). |
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Term
atom - mass
a) What is the mass number A?
b) Where do you find the mass number
for the atom of an element?
c) Do you include the number of electrons
in calculating the mass of an atom? |
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Definition
a) What is the mass number A? A = Z + N = #p+ + #n0
The mass number A is the number of protons #p+
+the number of neutrons #n0
b) Where to find the mass number for an element's atom?
in the Periodic Table of the Elements
c) Do you include the number of electrons in calculating the mass of an atom?
Relative to the mass of 1 proton or neutron,
the mass of 1 electron is too small to make a difference.
[1 proton has the mass of 1.840 electrons]
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mass g
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proton
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1.672621 *10-24
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neutron
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1.674927 *10−24
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electron
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0.000911 *10−24
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Term
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Definition
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Term
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Definition
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