Relative masses

Question 1

Atomic/ proton number

Answer 1

Number of protons in the nucleus of an atom of that element.
(If an uncharged atom it would show the number of electrons too)

Question 2

Z symbol

Answer 2

Atomic (proton) number

Question 3

Mass number/ nucleon number

Answer 3

A total of the number of protons and neutrons in the nucleus of that element

Question 4

A symbol

Answer 4

Mass number

Question 5

Isotopes

Answer 5

atoms of the same element with the same number of protons but a different number of neutrons

Question 6

Relative isotopic mass

Answer 6

Mass of an individual atom of an isotope compared to 1/12 the mass of a carbon-12 atom.

(Used in the context of isotopes)

Question 7

Relative atomic mass

Answer 7

The mean mass of an atom of an element compared to 1/12 the size of a carbon-12 atom

Question 8

Ar symbol

Answer 8

Stands for relative atomic mass

Question 9

How to find the relative atomic mass given the abundance

Answer 9

Add up (not multiply):
Relative isotopic mass x % abundance
Of all isotopes given
Divide by 100

Question 10

Molecular formula

Answer 10

Tells us which and how many atoms of which element in a covalent/ simple molecule
Eg CO2

Question 11

Empirical formula

Answer 11

Tells us the simplest whole number ratio of atoms of which element is in the compound
Includes giant structures: ionic lattices or giant covalent and simple

Question 12

Why do we use empirical formula?

Answer 12

It’s an easier way to represent which and how many atoms are in a compound without writing out the very large number

Question 13

Relative molecular mass

Answer 13

Used for molecular compounds: the sum of the relative atomic masses of all the atoms in a molecule compared to one twelfth of the mass of one atom of carbon-12

Question 14

Relative formula mass

Answer 14

Used for giant ionic compounds
Sum of relative mean masses of atoms in an ionic compound relative to 1/12 the size of a carbon 12 atom

Question 15

Symbol for relative formula mass and relative molecular mass

Answer 15

The same = Mr

Question 16

Why do we measure the masses of an atom in the scale of 1/12 of a carbon-12 atom?

Answer 16

Because 1/12 a carbon atom is 1 amu
And we measure the relative masses using this measurement
Also because mass of atoms are so small any over unit wouldn’t work

Question 17

Proton relative mass

Answer 17

1

Question 18

Proton charge

Answer 18

1+

Question 19

Proton location

Answer 19

Nucleus of atom

Question 19

Neutron relative mass

Answer 19

1

Question 20

Neutron charge

Answer 20

0

Question 21

Neutron location

Answer 21

Nucleus of atom

Question 22

Electron relative mass

Answer 22

1/1840

Question 23

Electron charge

Answer 23

1-

Question 24

Electron location

Answer 24

Orbitals

Question 25

Nucleon

Answer 25

Collective term for neutrons and protons

Question 26

What is the nucleon number

Answer 26

The same as mass number: Protons + neutrons added together

Question 27

How do we find the abundance of different isotopes?

Answer 27

Technique called mass spectrometry

Question 28

Do isotopes react the same way?

Answer 28

Yes because they have the same electron configuration in orbitals

Question 29

Avogadros constant

Answer 29

The number of atoms, molecules, ions or other chemical entities in one mole of a substance. L = 6.02 x 1023

Question 30

Relative atomic mass calculated from relative abundances

Answer 30

Sum of (isotopic mass x relative abundance) ---------------------------------------------------------------- Sum of relative abundances

Question 31

Why do relative masses have no units?

Answer 31

All measured to a standard and relative to 1/12 the size of a carbon 12 atom