Term
|
Definition
all matter in the universe is made of tiny particles called atoms.
there are 92 different atoms
these 92 different atoms combine to form different kinds of matter.
I.E. Gold is made up of only gold atoms! When matter is made of only one kind of atom, it is called an element. |
|
|
Term
|
Definition
made when combining two or more DIFFERENT elements
the bond formed is chemical so they cannot be easily separated.
I.E. H2O is made of 2 hydrogen atoms and one oxygen atom. |
|
|
Term
|
Definition
When two or more atoms of the SAME element combine together, we call them Molecules.
O2 = oxygen
H2 = hydrogen |
|
|
Term
|
Definition
Mixtures are substances which are made by combining two or more different materials that have not reacted chemically with each other and hence can be separated to individual components.
An example found in nature of a mixture is the salt water of oceans. Salt separates out when water is evaporated in salt beds. |
|
|
Term
| How to tell the difference between elements compounds and mixtures? |
|
Definition
| A MIXTURE is made from two or more substances that are chemically different and are not chemically joined. A COMPOUND is a substance formed when two or more ELEMENTS chemically react with each other to form chemical bonds between their atoms. |
|
|
Term
| Subatomic particles and their location |
|
Definition
Subatomic particles are particles that are smaller than the atom. Protons, neutrons, and electrons are the three main subatomic particles found in an atom.
Protons have a positive (+) charge. An easy way to remember this is to remember that both proton and positive start with the letter "P."
Bohr Model = 8 O 16 (oxygen) |
|
|
Term
|
Definition
The difference between atoms, ions and isotopes is the number of subatomic particles.
a typical atom has no electrical charge because the number of positively charged protons is the same as the number of negatively charged electrons. The number of electrons in an atom can change, though, either by gaining additional electrons from other atoms or by giving away one or more of its electrons to nearby atoms.
When an atom's number of electrons changes, the atom carries an electrical charge. This electrically charged atom is referred to as an ion.
Typically, an atom has the same number of protons and neutrons. Some atoms gain or lose a neutron. When the number of neutrons in an atom changes, an isotope is formed. Isotopes of an atom have different atomic masses and exhibit different properties, but they are still the same element. Isotopes differ from each other in the number of neutrons, not in the number of protons.
I.E. [image] |
|
|
Term
name the number of protons, electrons, neutrons, and the mass number of the following:
C-14
O -2
K+
30p |
|
Definition
C-14 ... 6 PROTONS, 8 NEUTRONS, MASS NUMBER 14
O -2
K+
30p |
|
|
Term
|
Definition
The average atomic mass of an element refers to the atomic masses of the isotopes of the element, taking into account the different abundances of the element's isotopes. The average atomic mass can be calculated using the following formula:
[image]
i.e. Given the relative abundance of the following naturally occurring isotopes of oxygen, calculate the average atomic mass of oxygen.
Oxygen-16: 99.76%
Oxygen-17: 0.037%
Oxygen-18: 0.204%
Divide the percentages by 100% to obtain a decimal figure and multiply each of the 3 masses (16,17 &18) by their respective decimal.
99.76% / 100% = 0.9976:
O:16 = 16 x 0.9976 = 15.9616.
0.037% / 100% = 0.0037:
O:17 = 17 x 0.00037 = 0.00629,
0.204% / 100% = 0.00204:
O:18 = 18 x 0.00204 = 0.03672.
.........................Total = 16.004 |
|
|
Term
| What Is the Difference Between Atomic Mass and Mass Number? |
|
Definition
There is a difference between the meanings of atomic mass and mass number. One is the average weight of an element and the other is the total number of nucleons in the atom's nucleus.
Atomic mass is also known as atomic weight. Atomic mass is the weighted average mass of an atom of an element based on the relative natural abundance of that element's isotopes.
Mass number is a count of the total number of protons and neutrons in an atom's nucleus. |
|
|
Term
| HOW DOES THE ATOMS LOCATION ON THE PERIODIC TABLE DETERMINE THE CHARGE OF THE ION IT FORMS |
|
Definition
|
|
Term
|
Definition
The octet rule refers to the tendency of atoms to prefer to have eight electrons in the valence shell. When atoms have fewer than eight electrons, they tend to react and form more stable compounds.
You can also think of it like this, the elements other than the noble gases( far right end of the periodic table He to Rn) have incomplete outer shells of electrons. Most elements strive to become a noble gas and have a stable configuration. To do this they either lose or gain electrons.
This is done by bonding either ionically , metallically or covalently. A ionic bond is a bond between a metal and non-metal where it is a give and take relationship. A metallic bond is between metals only where electrons are pooled together. A covalent bond occurs between non-metals only where they share electrons. In doing this they can obey the octet rule losing, gaining or sharing so that they can have an outer shell of eight electrons.
There are some exceptions. A few elements do not need the full 8 valence electrons to be stable (ex. hydrogen, boron, beryllium) and a few can be stable with more than 8 valence electrons (ex. phosphorus and sulfur). |
|
|
Term
|
Definition
| When two atoms interact, the electrons in the outermost shells, the valence electrons, of these two atoms are the first ones to come into contact with each other. The valence electrons are the ones that determine how an atom will react in a chemical reaction. |
|
|
Term
| What is the shorthand for carbon in organic chemistry? |
|
Definition
|
|
Term
What is the formula for calculating pH?
What is evaporation?
What is melting?
What is condensation? |
|
Definition
pH = log[H3O-]
When a liquid turns to a gas.
When a solid turns to a liquid.
When a gas turns to a liquid. |
|
|
Term
Nucleus of an element contains 8 protons. Its valency would be
Elements during chemical combination have a tendency-
Ions are formed from neutral atoms by-
Atom A and B have 3 and 6 electrons in the outer shell, the formula of the compound formed by A and B will be- |
|
Definition
2
Attain stable configuration
Loss or gain of electrons
A2B3 |
|
|
Term
Summary Of Periodic Table Trends (Atomic Radius, Ionization Energy, Electronegativity)
Atomic Radius
Ionization Energy
Electronegativity |
|
Definition
Atomic Radius
Period - atomic radius decreases as you go from left to right across a period.
Group - atomic radius increases as you go down a group
Ionization energy is the amount of energy required to remove the outmost electron. It is closely related to electronegativity
Period - ionization energy increases as you go from left to right across a period.
Group - ionization energy decreases as you go down a group.
Electronegativity
Electronegativity is an atom's 'desire' to grab another atom's electrons Period- electronegativity increases as you go from left to right across a period.
Group - electronegativity decreases as you go down a group. |
|
|
Term
| Of the following 3 elements, which is a metalloid - Si, Na, Cl. |
|
Definition
|
|
Term
| The elements in the modern periodic table are arranged in increasing order of ________ . |
|
Definition
|
|
Term
| The elements to the right side of the periodic table are ________. |
|
Definition
|
|
Term
| The number shown on the top part of each of the element squares in a periodic table is the ______. |
|
Definition
|
|
Term
| Mendeleev's periodic table was arranged in increasing order of the ________ of elements. |
|
Definition
|
|
Term
| The valence electrons determine the _______ properties of the element. |
|
Definition
|
|
Term
| The elements to the left side of the periodic table are ______. |
|
Definition
|
|
Term
| Vertical columns on the periodic table are called ______. |
|
Definition
|
|
Term
| Major periodic trends include: |
|
Definition
electronegativity, ionization energy, electron affinity, atomic radius, melting point, and metallic character.
Periodic trends, arising from the arrangement of the periodic table, provide chemists with an invaluable tool to quickly predict an element's properties. These trends exist because of the similar atomic structure of the elements within their respective group families or periods, and because of the periodic nature of the elements. |
|
|
Term
|
Definition
| a chemical property describing an atom's ability to attract and bind with electrons. |
|
|
Term
| DEFINE CATION AND ANION AND EXPLAIN HOW TO PREDICT |
|
Definition
Cations are ions with a net positive charge.
Cation Examples: Silver: Ag+, hydronium: H3O+, and ammonium: NH4+
Anions are ions with a net negative charge.
Anion Examples: hydroxide anion: OH-, oxide anion: O2-, and sulfate anion: SO42-
Sometimes you can predict whether an atom will form a cation or an anion based on its position on the periodic table. Alkali metals and alkaline earths always form cations. Halogens always form anions. Most other nonmetals typically form anions (e.g., oxygen, nitrogen, sulfur), while most metals form cations (e.g., iron, gold, mercury). |
|
|
Term
| Follow the steps below to write short cut version of electron configurations. |
|
Definition
Step 1: Find the element on the periodic table.
Step 2: Go back to the last noble gas that was passed (atomic number).
Step 3: Write the symbol of the noble gas in brackets to start your electron configuration. |
|
|
