Unit 3:

Question 1

Isotopes:

Answer 1

Different versions of an element (different # of neutrons / mad #. Same atomic number)

Question 2

How is an isotope more stable?

Answer 2

When it has a greater natural abundance

Question 3

How to find average atomic mass:

Answer 3

Isotope 1. Isotope2.
Amu = (mass)(%) + (mass)(%)
————————
100

Question 4

What is a mole:

Answer 4

A unit consisting of a group of atoms too small to count

Question 5

How much is 1 mole:

Answer 5

1 mole = 6.022 x 10 23

6.02214199. Avagadros number

Question 6

Why do we use the mole:?

Answer 6

When lab samples contain large #’s of particles which r sometimes too large + inconvenient to work with.

Question 7

Empirical formula:

Answer 7

The smallest ratio of atoms in a formula for a compound. (Simplest form)

Question 8

Molecular formula:

Answer 8

Gives the actual number of rad atom present in the compound. Molecular is the “true formula”