Periodic Trends

Question 1

Atomic Radius Definition

Answer 1

Half of the distance from nucleus to nucleus.

Question 2

Atomic Radius Definition

Answer 2

Half of the distance from nucleus to nucleus.

Question 3

Atomic Radius Trend

Answer 3

Decreases across a period, Increases down a group.

Question 4

Atomic Radius Explanation

Answer 4

Down a group, there are more electrons and they need more space to spread out. Across a period, the greater number of protons pulls the electrons closer towards the nucleus.

Question 5

Ionic Radius Trend

Answer 5

Cations, since they have fewer electrons, are smaller than their parent atom. Anions, since they have more electrons, are larger than their parent atoms.

Question 6

Ionic Radius Trend

Answer 6

Cations, since they have fewer electrons, are smaller than their parent atom. Anions, since they have more electrons, are larger than their parent atoms.

Question 7

Ionization Energy Definition

Answer 7

The minimum energy required to remove an electron from the ground state of the isolated gaseous atom or ion.

Question 8

Ionization Energy Trend

Answer 8

Increases across periods and decreases down groups.

Question 9

Ionization Energy Explanation

Answer 9

Across a period, the protons pull harder on the electrons. Therefore, you need more energy to remove them. Down a group, the electrons are farther from the nucleus and therefore can be stripped away more easily than electrons that are closer to the nucleus.

Question 10

Electron Affinity Definition

Answer 10

The energy change that occurs when an electron is added to a gaseous atom

Question 11

Electron Affinity Trend

Answer 11

The trend is not as clear, but ROUGHLY electron affinity increases across a period. For the alkali metals and the bottom half of the oxygen group, carbon group, and halogens, electron affinity decreases down the group. For alkaline earth metals, the boron group, the nitrogen group, and the top halves of the oxygen group and halogens, electron affinity increases down a group.

Question 12

Electron Affinity Trend

Answer 12

The trend is not as clear, but ROUGHLY electron affinity increases across a period. For the alkali metals and the bottom half of the oxygen group, carbon group, and halogens, electron affinity decreases down the group. For alkaline earth metals, the boron group, the nitrogen group, and the top halves of the oxygen group and halogens, electron affinity increases down a group.

Question 13

Electron Affinity Explanation

Answer 13

The more energy it requires to gain an electron, the higher the electron affinity is.

Question 14

Electronegativity Definition

Answer 14

The ability of an atom IN A MOLECULE to attract electrons to itself.

Question 15

Electronegativity Trend

Answer 15

Increases across a period, Decreases down a group

Question 16

Electronegativity Explanation

Answer 16

The stronger the nucleus pulls at its electrons, the more it wants electrons (exception being noble gases) and thus the greater its electronegativity.