Question

1. examine the image below.

what are the dots in the image used to represent?
a. atomic mass
b. protons
c. the structure of the nucleus
d. valence electrons

1. how does lowering the temperature affect most chemical reactions?

a. it speeds them up.
b. it changes their products.
c. it slows them down.
d. it increases the amount of product.
how many electrons are needed in the outer energy level of most atoms for the atom to be chemically stable?
a. 2
b. 4
c. 6
d. 8

1. blue litmus paper turns red in the presence of an acid. what is the litmus paper considered to be?

a. a base
b. an indicator
c. a soap
d. an acid

Explanation:

1. Lewis dot structures use dots to represent valence electrons.
2. Lowering temperature reduces the kinetic energy of reactant particles, slowing down most chemical reactions.
3. The octet rule states that most atoms need 8 electrons in their outer energy level to be chemically stable.
4. Litmus paper changes color in the presence of acids or bases, so it is an indicator.

Answer:

1. D. valence electrons
2. C. It slows them down.
3. D. 8
4. B. An indicator