Question

question 21 (1 point)
what are the group 1a and group 7a elements examples of?
o a noble gases
b nonmetallic elements
o c representative elements
d transition elements

question 22 (1 point)
of the elements fe, hg, u, and te, which is a representative element?
o a hg
b te
o c u
d fe

question 23 (1 point)
how does atomic radius change from top to bottom in a group in the periodic table?
o a it first increases, then decreases.
b it tends to decrease.
o c it first decreases, then increases.
d it tends to increase.

Explanation:

• Question 21:
• Noble gases are in Group 8A. Group 1A has metals (except hydrogen) and Group 7A has non - metals. Representative elements are elements from Groups 1A - 8A (excluding the transition metals). Group 1A and 7A are part of the representative elements. Non - metallic elements only refer to a subset (Group 7A is non - metallic but Group 1A has metals). Transition elements are in the d - block (Groups 3B - 12B).
• Question 22:
• Fe (iron) is a transition metal (Group 8B). Hg (mercury) is a transition metal (Group 2B). U (uranium) is an actinide (a type of inner - transition metal). Te (tellurium) is in Group 6A, which is part of the representative elements.
• Question 23:
• As we move from top to bottom in a group in the periodic table, new electron shells are added. The increase in the number of electron shells overcomes the increase in nuclear charge (due to more protons). So, the atomic radius tends to increase.

Answer:

• Question 21: C. representative elements
• Question 22: B. Te
• Question 23: D. It tends to increase.