1How does first ionization energy change down a group in the periodic table?
First ionization energy decreases down a group.
2How does first ionization energy change across a period?
First ionization energy generally increases across a period.
3What happens to first ionization energy down Group 2, and why?
Ionization energy decreases down Group 2 because extra electron shells increase shielding and distance from the nucleus.
4Why does ionization energy increase across a period?
The number of protons increases, strengthening the attraction between the nucleus and outer electrons.
5Do additional electrons across a period add significant shielding?
No, extra electrons are at similar energy levels, so shielding remains nearly constant.
6Where are the small drops in ionization energy across a period?
Small drops occur between groups 2 and 3, and between groups 5 and 6.
7Why is there a drop in ionization energy between groups 2 and 3?
The outer electron in group 3 elements is in a 3p orbital, which is higher in energy and farther from the nucleus with additional shielding from 3s electrons.
8What evidence does the drop in ionization energy between groups 2 and 3 provide?
It provides evidence for the existence of electron sub-shells.
9Why is there a drop in ionization energy between groups 5 and 6?
In group 6, electrons start pairing in orbitals, causing electron repulsion that makes it easier to remove one electron.
10How does electron repulsion affect sulfur's ionization energy?
In sulfur, an electron is removed from a paired orbital, where repulsion makes it easier to remove than in singly-occupied orbitals like phosphorus.
11In phosphorous, from what type of orbital is the electron removed?
The electron is removed from a singly-occupied orbital.
12What factors influence the ionization energy trend down Group 2?
Increased shielding from inner electrons and greater distance from the nucleus.
13Why does the 3p orbital in aluminum lead to lower ionization energy than magnesium?
The 3p orbital has slightly higher energy and is farther from the nucleus, with additional shielding from 3s electrons.
14What effect does nuclear charge have on ionization energy across a period?
An increasing nuclear charge raises the ionization energy by strengthening the attraction to outer electrons.