Question

Helium (He) and neon (Ne) are elements in Group 8A of the periodic table. How do the electron dot diagrams of these elements compare?

A. The electron dot diagram of helium has six fewer electrons than the electron dot diagram of neon.
B. The electron dot diagram of helium has eight fewer electrons than the electron dot diagram of neon.
C. Both the electron dot diagram of helium and the electron dot diagram of neon have two dots.
D. Both the electron dot diagram of helium and the electron dot diagram of neon have eight dots.

Answer 1

Helium (He) and neon (Ne) are elements in Group 8A of the periodic table. How do the electron dot diagrams of these elements compare?

A. The electron dot diagram of helium has six fewer electrons than the electron dot diagram of neon.

B. The electron dot diagram of helium has eight fewer electrons than the electron dot diagram of neon.

C. Both the electron dot diagram of helium and the electron dot diagram of neon have two dots.

D. Both the electron dot diagram of helium and the electron dot diagram of neon have eight dots.

Answer 2

A. The electron dot diagram of helium has six fewer electrons than the electron dot diagram of neon.
Helium's dot diagram has two dots because it has two valence electrons, which completes it's shell because the first shell only fits two electrons.
The dot diagram of neon has eight valence electrons because it has 10 electrons: 2 go in the first shell, 8 go in the outer shell.