2.2 Relative Mass

Question 1

What isotope is taken as the standard against all other atoms are compared to?

Answer 1

The carbon-12 isotope (12/6 C)

Question 2

Why is the Carbon-12 Atom so important?

Answer 2

The mass of a Carbon-12 Atom is defined as exactly 12 atomic mass units (12U)

Question 3

What is the mass of a p+ & n?

Answer 3

1u

Question 4

Define relative isotopic mass.

Answer 4

Relative isotopic mass is the mass of an isotope relative to 1/12th if the mass of an atom of Carbon 12

Question 5

What does mostly relative isotopic mass equal?

Answer 5

The mass number (p+n) A

Question 6

Define relative atomic mass

Answer 6

The weighted mean of a mass of an atom of an element relative to 1/12th of the mass of an atoms of carbon-12

Question 7

What does mean mass depend on?

Answer 7

• The abundance of each isotope

* The relative isotopic mass of each isotope

Question 8

What is the symbol for relative atomic mass?

Answer 8

Ar

Question 9

what is the equation for relative atomic mass?

Answer 9

Ar = (relative isotopic mass of isotope 1 X percentage abundance of isotope 1) + (relative isotopic mass of isotope 2 x percentage abundance of isotope 2) / 100