relative atomic mass

Question 1

what is mass given in (relative terms) ?

Answer 1

relative to the c12 isotope which is an international standard

Question 2

why c12?

Answer 2

it is an international standard and atomic mass is measured in unified atomic mass unit (u). C12 is 12u
and 1/12 of C12 is 1u.

Question 3

what is Relative isotope mass (RIM)?

Answer 3

the mass of an atom of an isotope compared with 1/12th of the mass of an atom of C12.
- for an isotope it is always the same as the mass number

Question 4

what is Relative atomic mass (RAM)?

Answer 4

the weighted mean mass of an atom of an element compared with 1/12th of the mass of an atom of carbon-12

Question 5

what are many atoms?

Answer 5

a mixture of isotopes so atomic mass factors this in through :
abundance x mass number + abundance x mass number / 100
if the abundance is not calculated as 0.x

Question 6

what is Relative molecular mass (RMM)?

Answer 6

some elements are composed of simple elements e.g. diastolic-> 
e.g.
Cl2 is diatomic
-> mass number = 35.5 x2 
= 71

Question 7

what is relative formula mass? (RFM)

Answer 7

it is similar to Mr. and applies to ionic compounds when the RAM of each formula unit is calculated

Question 8

what is the RFM of NaCl?

Answer 8

Na:23
Cl:35.5
35.5+23=58.5

Question 9

what is the RIM, RAM, RMM and RFM of chlorine?

Answer 9

RIM RAM RFM RMM(NaCl)
Cl: 35 35.5 71 58.5
Cl: 37

Question 10

what is the RFM of Na3PO4?

Answer 10

Na: 23x3
=69
P:31
O:16x4
=64
-> 31+69+64=164

Question 11

on the periodic table, the mass number of magnesium is 24.31 why is it not an integer?

Answer 11

the mass number on the periodic table is the Relative Isotopic Mass MEANING that 2 or more isotopes of magnesium contribute to this mass (making it not an integer).