Question

question 1 (1 point)
in the periodic table hydrogen is placed and group 1a and helium is placed in group 8a. the most likely reason for this is
a hydrogen and helium are both metals.
b hydrogen has one outer shell electron and helium has a full valence shell of electrons.
c hydrogen and helium are both gases.
d hydrogen has one outer shell electron and helium has 8 electrons in its valence shell

question 2 (1 point)
rank the following in order of increasing atomic radius

1. ga
2. tl
3. b

Explanation:

Question 1:

Hydrogen has 1 outer - shell electron and is placed in Group 1A. Helium has a full valence shell (2 electrons for the first shell) and is in Group 8A. Option a is incorrect as hydrogen is not a metal. Option c is not the main reason for their group placement. Option d is wrong as helium has 2 electrons in its valence shell, not 8.

Question 2:

Atomic radius increases down a group and decreases across a period. Boron (B) is in Period 2, Gallium (Ga) is in Period 4, and Thallium (Tl) is in Period 6. So, the order of increasing atomic radius is B < Ga < Tl.

Answer:

Question 1:

b. Hydrogen has one outer shell electron and helium has a full valence shell of electrons

Question 2:

1. B, 1. Ga, 2. Tl