Question

which of the following factors contributes to the increase in atomic size within a group in the periodic table as the atomic number increases?

an increase in number of protons

an increase in size of the nucleus

fewer electrons in the highest occupied energy level

more shielding of the electrons in the highest occupied energy level

question 6

which statement is true about electronegativity?

electronegativity is the ability of an anion to attract another anion.

electronegativity generally increases as you move from top to bottom within a group.

electronegativity generally is higher for metals than for nonmetals.

electronegativity generally increases from left to right across a period.

Explanation:

• For the first question:
• As atomic number increases within a group, the number of electron shells increases. Inner - shell electrons shield the outer - shell electrons (in the highest occupied energy level) from the nuclear charge. More shielding means less attraction between the nucleus and the outermost electrons, allowing the atom to expand.
• An increase in protons (and nuclear size) would actually tend to pull electrons in (if shielding were constant). And within a group, the number of electrons in the highest occupied energy level is the same for neutral atoms of elements in the same group.
• For the second question:
• Electronegativity is the ability of an atom in a chemical bond to attract electrons to itself (not an anion attracting another anion).
• As you move from top to bottom in a group, electronegativity generally decreases (due to increased shielding and larger atomic size).
• Non - metals generally have higher electronegativity than metals (metals tend to lose electrons rather than strongly attract them in a bond).
• As you move from left to right across a period, the nuclear charge increases, and the atomic radius decreases (less shielding as electrons are added to the same shell), so atoms have a greater ability to attract electrons, and electronegativity generally increases.

Answer:

• First question: more shielding of the electrons in the highest occupied energy level.
• Second question: Electronegativity generally increases from left to right across a period.