Question

an atomic mass unit (amu) is defined as the *
mass of a carbon atom
one-twelfth the mass of a carbon atom
one-twelfth the mass of a hydrogen atom
mass of a hydrogen atom

what is the lewis diagram for oxygen? *
image of a word document with lewis diagram options a to e
c
b
e
d
a

Explanation:

First Question (Atomic Mass Unit Definition)

The definition of an atomic mass unit (amu) is one - twelfth the mass of a carbon - 12 atom. A carbon atom's mass is not the definition of amu, and hydrogen atom's mass is not related to the amu definition. So the correct option is the one stating one - twelfth the mass of a carbon atom.

Second Question (Lewis Diagram for Oxygen)

Oxygen has 6 valence electrons. In a Lewis diagram, the valence electrons are represented as dots around the symbol. The correct Lewis diagram for oxygen should have 6 valence electrons. Option d shows the oxygen symbol (O) with 6 dots (2 pairs and 2 single dots) which is correct as oxygen has 6 valence electrons. Option a has too few, b has too few, c has an incorrect arrangement, and e has an incorrect number of dots (it looks like 8 which would be for an ion or a different configuration).

Answer:

B. one - twelfth the mass of a carbon atom