3.2 isotopes

Question 1

why are elements different?

Answer 1

they have different numbers of protons

Question 2

atomic number

Answer 2

the number of protons in the nucleus of an atom of that element

Question 3

mass number

Answer 3

the total number of protons in an atom

Question 4

how do you calculate the number of neutrons?

Answer 4

mass number - atomic number

Question 5

isotopes

Answer 5

-atoms that have the same number of protons but different numbers of neutrons
-different mass numbers
-chemically alike

Question 6

standard reference isotope

Answer 6

Carbon-12

Question 7

how many atomic mass units does carbon-12 have?

Answer 7

12

Question 8

atomic mass unit

Answer 8

1/12 the mass of a Carbon-12 atom (the standard for all units)

Question 9

atomic mass

Answer 9

a weighted average mass of the atoms in a naturally occurring sample of the element

Question 10

weighted average

Answer 10

reflects both the mass and the relative abundance of the isotopes as they occur in nature

Question 11

how do you calculate the atomic mass of an element?

Answer 11

mass x natural abundance
add the products