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chemical periodicity
notecards on chemical periodicity
63
Chemistry
10th Grade
02/05/2011

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Term
What is probably the most useful tool for chemists?
Definition
the periodic table
Term
______play most important role in determining the physical and chemical properties of an element.
Definition
electrons
Term
Arrangment of elements in the periodic table depends on the ______.
Definition
 properties of elements
Term
What are the four categories for classifying elements based on electron configuration?
Definition
noble gases, representative elements,transisiton metals, inner transisiton metals
Term
What is the group number equal to?
Definition
the number of electrons in the outermost energy level
Term
______are metallic elements with outermost s sublevel and nearby d sublevel contain electrons.
Definition
transition metals
Term
Transisiton metals make up ______.
Definition
group B elements
Term
Transistion metals are characterized by the addition of electrons in _____..
Definition
d orbitals
Term
______are metallic elements with outermost s sublevel and nearby f sublevel generally contain electrons.
Definition
innertransition metals
Term
What are inner transistion metals characterized by?
Definition
the filling of the f orbital
Term
The s block corresponds to the the groups ____and____elements.
Definition
one a and two a
Term
What each period number represent?
Definition
principle energy levels
Term
Atoms do not have_____and the _____of an atom cannot be directly measured.
Definition
definite size; radius
Term
______is used to estimate atomic radii of crystalline structures
Definition
x-ray diffraction
Term
For diatomic molecules, what is the radius?
Definition
1/2 the distance between the nuclei of the two atoms
Term
Atomic radius indicates_____.
Definition
relative size
Term
Atomic size generally _____as you move down a group in the periodic table.
Definition
increases
Term
What are the two competing factors that affect atomic size?
Definition
electron shielding and effective nuclear charge
Term
Why does electron sheilding tend to increase the atomic radius?
Definition
because electrons added to higher energy levels don't feel full force of nuclear charge
Term
Outer electrons are _____from the nuclear charge.
Definition
shielded
Term
Why does effective nuclear charge tend to shrink atomic size?
Definition
because of the attractive force between the nucleus and the electrons
Term
What happens to the shielding as electrons are added to higher principle energy levels?
Definition
the shielding of electrons offsets the increased charge of the nucleus
Term
Why are cations smaller than the neutral atoms?
Definition
because of the attraction of the nucleus on fewer electrons
Term
Why are anions larger than the neutral atom?
Definition
because the inner electrons shield the extra electron
Term
Atomic size generally _____as you move from left to right across the period.
Definition
decreases
Term
The shielding effect is ____across a period.
Definition
constant
Term
The increased nuclear charge pulls the outermost electrons inward. What does this do?
Definition
decreases the atomic size
Term
The energy required to overcome the nuclear charge and remove an electron from a gaseous atom is called the______.
Definition
ionization energy
Term
What is first ionization energy?
Definition
the energy required to remove the outermost electron is
Term
What is second ionization energy?
Definition
 the energy required to remove the second outermost electron
Term
What is the main difference between the first and second inonization energies?
Definition
it easy to remove on electron, but difficult to remove others
Term
What two factors affect ionization ergy?
Definition
nuclear charge and distance from the nucleus
Term
Why does first ionization energy generally decrease down a group?
Definition
because as you move down the group, the electrons are farther from the nucleus and more easily removed
Term
Why does first ionization energy generally increase from left to right across a period?
Definition
 because nuclear charge increases and shielding is constant which causes a greater attraction of the nucleus for electrons, making it harder to remove an electron
Term
Whether an atom gains or loses an electron affects its______.
Definition
ionic size
Term
Why are anions generally larger than the neutal atoms?
Definition
the nuclear attraction is less for the increased number of electrons
Term
____generally increases down the group.
Definition
ionic radius
Term
From left to right across a period ____ gradually decrease in size.
Definition
cations
Term
The_____of an element is the tendency of the atoms of the element to attract electrons when bonded to another atom.
Definition
electronegativity
Term
Where does the electronegativity of representative elements decrease? When does it increase?
Definition
decreses down the group; increases left to right across the period.
Term
When does atomic radius increase? When does it decrease?
Definition
down a group; down a period
Term
What is the difference between a group and a period?
Definition
a group is the column and a period is the row
Term
Which are larger: cations or the neutral atoms from which they form?
Definition
neutral atoms from which they form
Term
What does electronegativity measure?
Definition
the ability of a bonded atom to attract electrons to itself
Term
When does electronegativity decrease? When does it increase?
Definition
down the group; across the period
Term
Would halogens have low or high electronegativities?
Definition
high
Term
How many orbitals are the 4p energy level?
Definition
three
Term
Do electrons pair up in each orbital before filling additional ones?
Definition
no
Term
To occupy the same orbital, what must electrons have?
Definition
opposite signs
Term
Bohr discovered that electrons have fixed amounts of energy, they do not_____energy and cannot fall into the ____.
Definition
nucleus
Term
What is a quantam of energy?
Definition
the amount of energy needed to raise an electron to the next higher level
Term
ARe energy levels evenly spaced?
Definition
no
Term
When is the electron cloud more dense?
Definition
when the probability of finding an electron is high
Term
Regions in which electrons are likely to be found are called______.
Definition
atomic orbitals
Term
Within each principle energy level, electrons occupy _____.
Definition
energy sublevels
Term
Atomic orbitals are designated with what letters?
Definition
spdf
Term
What shape is the s orbital? What shape is the p orbital? What shape is the d orbital? What shape is the f orbital?
Definition
spherical; dumbell shaped; clover leaf; very complex
Term
What does the principle quantam number tell about electrons?
Definition
the maximum number of electrons in that principle energy level
Term
What letter represents the principle quantam number?
Definition
n
Term
How many electrons are in the s sublevel? p? d? f?
Definition
2; 6; 10; 14
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