Atomic trends in atomic properties Flashcards
What is effective nuclear charge (ENC)
The force of attraction between the electrons and nucleus. The attraction of the negative valence electrons with the positive nucleus of an atom
Valences electrons ________ to positive protons in nucleus = Higher ENC
closer
An example of Lower ENC
Negative valence electrons further away from positive protons in nucleus, which results in a low ENC
positive protons increase as we go from left to right, # of valence electrons increase from left to right. Therefore ______ ENC
Higher
Effective nuclear charge decreases the ________ the electrons are from the positive nucleus.
further
Effective nuclear charge ______ across a period. (left to right)
increase
What is atomic radius?
Atomic radius is the distance from the nucleus to the outermost valence electrons.
Going down a group, the atomic radius increases. Why? (2 reasons) (atomic radius)
- Each atom has one additional orbital
- Valence electrons are further away from the nucleus resulting in low ENC
Going across the period (right to left), the radius increases. Why? (ionic radius)
Less positive protons in the nucleus –> weaker to pull on valence electrons, thus low ENC
Define ionic radius
Ionic radius refers to the size of an ion
Explain metal cations during ionic radius
When a metal loses an electron, the cation has one less energy level; making cation smaller (resulting in a high ENC)
Explain non-metal anions during ionic radius
When a non-metal gains electrons, the anion experiences less attraction since electrons repel each other, resulting in a low ENC
If an ion has extra electrons, will the radius be small or large?
large
Define ionization energy
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.
The easier it is to remove an electron from an atom, the ______ the ionization energy. (lower or higher)
lower
Li (g) + energy –> Li^+(g) + e-
True or False
True
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)
decrease, more
In ionization energy, what does it mean if we say “the ENC increases across a period”
Need more energy to pull away electron
Noble gases have the lowest ionization energy. True or False
False
Noble gases have the highest ionization energy because they have a full valence shell
The closer an atom is to a full valence orbital, the _______ the ionization energy
higher
Define electron affinity
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
F(g) + e- –> F^- (g) + energy
True or False (electron affinity)
True
Ionization energy and electron affinity both occur in the liquid form. True or False
False
Both occur in the gaseous state
The closer the valence orbital is to the nucleus, the higher the electron affinity. Why?
Higher ENC
This means that the force of attraction is very strong
As you go across a period (left to right), the electron affinity decreases. Why? Give 2 reasons
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
Noble gases have a full valence electron, therefore they have no electron affinity
True or False
True
Group 1 elements are the least reactive metals. True or False
False
Chemical reactivity _______ in group 1 as ionization energy decreases and effective nuclear charge _________
(Hint: easy to lose electrons)
increases, decreases
Which group is the most non-reactive?
Group 7A
Chemical reactivity increases up group 7A as electron affinity _____ and effective nuclear charge increases
increases
Why is group 8 the least reactive group on the periodic table?
Already have a full valence orbital, therefore no need to react (no need to lose or gain electrons)
Most reactive metal on the periodic table
Francium
Most reactive non-metal on the periodic table
Fluorine
