Question

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

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

question 31 (1 point)
which of the following statements is true about ions?
o a anions form when an atom loses protons.
o b anions form when an atom gains protons.
o c catlons form when an atom gains electrons.
o d cations form when an atom loses electrons

Explanation:

Question 29

Atomic radius decreases across a period (from left to right) and increases down a group. Bromine (Br) and chlorine (Cl) are in Group 17. Sulfur (S) is in Group 16 and Selenium (Se) is in Group 16 (below S). Among Br and Cl, Cl is higher up in the group (Period 3) while Br is in Period 4. So Cl has a smaller atomic radius than Br. S is in Period 3, Group 16 (left of Cl in the period). As we move from left (S) to right (Cl) in a period, atomic radius decreases. So Cl has a smaller radius than S. Se is below S in the group, so Se has a larger radius than S.

A cation is formed when an atom loses electrons. Since electrons are negatively - charged, losing electrons gives the ion a net positive charge. A neutral atom has equal number of protons (+) and electrons (-). When it loses electrons (negative charge), the positive charge (from protons) is in excess.

• Anions are formed when an atom gains electrons (not protons, because protons are in the nucleus and are not easily gained or lost in chemical reactions).
• Cations are formed when an atom loses electrons. When an atom loses electrons (negative charge), it has a net positive charge (since the number of protons (positive) is more than the number of electrons (negative) in the ion)

Answer:

d. chlorine

Question 30