Atomic Radii
What happens to atomic radius as you move down a group on the periodic table and why?
It increases because new electron shells are added
What is ionization energy?
The energy required to remove an electron from a gaseous atom.
What is meant by electron affinity?
The energy change when an atom gains an electron.
Which element has the highest electronegativity?
Fluorine (F)
Which group on the periodic table contains the noble gases?
Group 18.
Which atom has the largest atomic radius: Na, Mg, or Al? Explain.
Na (Sodium)
Which element has a higher first ionization energy: Li or Be?
Li.
Why do noble gases have positive or near zero electron affinity values?
They have a complete and stable outer electron shell
Which type of bond results when the difference in electronegativity between two atoms is greater than 1.8?
An ionic bond.
How are elements arranged in the periodic table?
By atomic number.
Which atomic radius is larger: O²⁻ or O? Why?
O²⁻ because it has a lower effective nuclear charge causing it to be larger.
Explain the phenomenon of effective nuclear charge on atoms.
ENC is the net positive force exerted and felt by one singular electron.
What is the periodic trend of electron affinity?
Electron affinity generally increases (becomes more negative) across a period from left to right and decreases down a group.
Which factor primarily determines electronegativity?
Effective Nuclear Charge, an atom with a higher ENC exerts a stronger pull on its own electrons and, consequently, a stronger attraction for the shared electrons in a chemical bond.
Who is credited for creating the modern periodic table?
(bonus points if you can name one of the very first inventors)
Henry Moseley
(Dmitri Mendeleev)
Which atom has the smaller atomic radius: Ga or Al?
Despite being below Al on the periodic table, Ga’s filled 3d¹⁰ subshell causes poor shielding, so the effective nuclear charge pulls outer electrons in tighter.
Rank the following in increasing first ionization energy: Mg, Al, Si. Explain.
Al < Mg < Si. Al’s 3p¹ electron is easier to remove than Mg’s 3s², and Si has higher nuclear charge.
Why is the electron affinity of Group 2 elements near zero or positive?
They have filled s subshells and would need to start a higher-energy p subshell.
Who is accredited for the idea of Electronegativity?
Linus Pauling
List any 3 properties of a metal.
- can hold a lot of weight (strong)
- are sonorous (sound lingers)
- good conductors of heat
Explain why transition metals show only a slight decrease in atomic radius across a period.
Added electrons go into inner d orbitals, which shield outer electrons, moderating the trend.
Why does oxygen have a slightly lower first ionization energy than nitrogen, despite being to its right on the periodic table?
Oxygen’s 2p⁴ configuration has electron pairing repulsion, making it easier to remove one
Which has the greater electron affinity: chlorine (Cl) or chloride ion (Cl⁻)?
Cl because Cl⁻ already has a full shell, so adding another electron requires energy input.
Why do atoms have different electronegativities?
Atoms have different electronegativities due to variations in their nuclear charge, atomic size, and electron shielding. A higher nuclear charge increases electronegativity, while greater electron shielding + atomic radius decrease it because the nucleus's pull on bonding electrons is weaker.
Why does Argon come after Chlorine on the periodic table even though its atomic mass is smaller?
The table is arranged by atomic NUMBER not atomic mass, argon has one more proton than chlorine therefore placing it later.