Atomic trends in atomic properties

Question 1

What is effective nuclear charge (ENC)

Answer 1

The force of attraction between the electrons and nucleus. The attraction of the negative valence electrons with the positive nucleus of an atom

Question 2

Valences electrons ________ to positive protons in nucleus = Higher ENC

Answer 2

closer

Question 3

An example of Lower ENC

Answer 3

Negative valence electrons further away from positive protons in nucleus, which results in a low ENC

Question 4

positive protons increase as we go from left to right, # of valence electrons increase from left to right. Therefore ______ ENC

Answer 4

Higher

Question 5

Effective nuclear charge decreases the ________ the electrons are from the positive nucleus.

Answer 5

further

Question 6

Effective nuclear charge ______ across a period. (left to right)

Answer 6

increase

Question 7

What is atomic radius?

Answer 7

Atomic radius is the distance from the nucleus to the outermost valence electrons.

Question 8

Going down a group, the atomic radius increases. Why? (2 reasons) (atomic radius)

Answer 8

1. Each atom has one additional orbital
2. Valence electrons are further away from the nucleus resulting in low ENC

Question 9

Going across the period (right to left), the radius increases. Why? (ionic radius)

Answer 9

Less positive protons in the nucleus –> weaker to pull on valence electrons, thus low ENC

Question 10

Define ionic radius

Answer 10

Ionic radius refers to the size of an ion

Question 11

Explain metal cations during ionic radius

Answer 11

When a metal loses an electron, the cation has one less energy level; making cation smaller (resulting in a high ENC)

Question 12

Explain non-metal anions during ionic radius

Answer 12

When a non-metal gains electrons, the anion experiences less attraction since electrons repel each other, resulting in a low ENC

Question 13

If an ion has extra electrons, will the radius be small or large?

Answer 13

large

Question 14

Define ionization energy

Answer 14

Ionization energy is the minimum amount of energy required to remove an electron from an atom in its gaseous state. The harder to remove the electrons, the higher the ionization energy.

Question 15

The easier it is to remove an electron from an atom, the ______ the ionization energy. (lower or higher)

Answer 15

lower

Question 16

Li (g) + energy –> Li^+(g) + e-
True or False

Answer 16

True

Question 17

Distance of valence electrons from the nucleus ______ (decrease or increase) as you go up, therefore ENC increases and _______ (more or less) attraction for the valence electrons (Ionization energy)

Answer 17

decrease, more

Question 18

In ionization energy, what does it mean if we say “the ENC increases across a period”

Answer 18

Need more energy to pull away electron

Question 19

Noble gases have the lowest ionization energy. True or False

Answer 19

False
Noble gases have the highest ionization energy because they have a full valence shell

Question 20

The closer an atom is to a full valence orbital, the _______ the ionization energy

Answer 20

higher

Question 21

Define electron affinity

Answer 21

The amount of energy released when a neutral atom gains an electron. The greater the electron affinity, the more an atom wants to gain an electron

Question 22

F(g) + e- –> F^- (g) + energy
True or False (electron affinity)

Answer 22

True

Question 23

Ionization energy and electron affinity both occur in the liquid form. True or False

Answer 23

False
Both occur in the gaseous state

Question 24

The closer the valence orbital is to the nucleus, the higher the electron affinity. Why?

Answer 24

Higher ENC
This means that the force of attraction is very strong

Question 25

As you go across a period (left to right), the electron affinity decreases. Why? Give 2 reasons

Answer 25

Octet rule –> electron affinity is high as atoms are closer to a full valence orbital
ENC also increases as we go from left to right. There are more protons. Therefore, more valence electron attraction

Question 26

Noble gases have a full valence electron, therefore they have no electron affinity
True or False

Answer 26

True

Question 27

Group 1 elements are the least reactive metals. True or False

Answer 27

False

Question 28

Chemical reactivity _______ in group 1 as ionization energy decreases and effective nuclear charge _________
(Hint: easy to lose electrons)

Answer 28

increases, decreases

Question 29

Which group is the most non-reactive?

Answer 29

Group 7A

Question 30

Chemical reactivity increases up group 7A as electron affinity _____ and effective nuclear charge increases

Answer 30

increases

Question 31

Why is group 8 the least reactive group on the periodic table?

Answer 31

Already have a full valence orbital, therefore no need to react (no need to lose or gain electrons)

Question 32

Most reactive metal on the periodic table

Answer 32

Francium

Question 33

Most reactive non-metal on the periodic table

Answer 33

Fluorine