Question

question 28 (1 point)
which of the following factors contributes to the increase in atomic size within a group in the periodic table as the atomic number increases?
o a an increase in size of the nucleus
b an increase in number of protons
o c fewer electrons in the highest occupied energy level
d more shielding of the electrons in the highest occupied energy level

question 29 (1 point)
which of the following elements has the smallest atomic radius?
o a bromine
b selenium
o c chlorine
d sulfur

question 30 (1 point)
what is the charge of a cation?
o a a negative charge
b the charge depends on the size of the nucleus.
o c a positive charge
d no charge

question 31 (1 point)
which of the following statements is true about ions?

Explanation:

• Question 28: As atomic number increases within a group, electron - shielding (where inner electrons shield outer electrons from nuclear pull) increases. This causes the outermost electrons to be less tightly held, increasing atomic size. Options a (nucleus size increase has negligible effect on atomic size compared to shielding), b (proton increase would pull electrons in, but shielding overcomes this in a group), and c (same number of electrons in highest occupied energy level in a group) are incorrect.
• Question 29: Atomic radius decreases across a period (left - to - right). Sulfur (S), selenium (Se), bromine (Br), and chlorine (Cl) are considered. Chlorine is in a higher period (period 3) compared to bromine (period 4) and selenium (period 4). Among sulfur (group 16) and chlorine (group 17) in period 3, chlorine has a smaller radius as it has more protons pulling electrons in.
• Question 30: A cation is formed when an atom loses electrons. Since electrons are negatively charged, losing them results in a net positive charge. A negative charge (a) is for anions, charge depending on nucleus size (b) is incorrect (charge depends on electron loss/gain), and no charge (d) is for neutral atoms.

Answer:

• Question 28: d. more shielding of the electrons in the highest occupied energy level
• Question 29: c. chlorine
• Question 30: c. a positive charge