# page 41 and 42

HideShow resource information
• Created by: Abi14
• Created on: 01-04-14 17:50
what is the realtive mass of protons and neutrons?
1
1 of 8
what is the realtive mass of electrons?
almost nothing, this is why we only use the protons and neutrons when working out the mass of an atom.
2 of 8
what is an isotope?
atoms of the same element have the same atomic number. the number of protons and electrons in an atom must always be the same, but there can be a different number of neutrons. this is so the charges still balance out and the atom still has no charge.
3 of 8
what do we use realtive atomic masses to compare?
the masses of different atoms. the relative atomic mass of an element in grams is called one MOLE of atoms of the element.
4 of 8
what is the relative atomic mass?
the relative atomic mass of an element is an average value that depends on the isotopes the element contains. however when rounded to a whloe number it is often the same as the mass number of the main isotope of the element.
5 of 8
how do you work out the relative formula mass of a compound?
by adding up the relative atomic masses of the elements in it.
6 of 8
what is a mole?
one mole of any substancee is its relative formula mass in grams.
7 of 8
what is the mass of one mole od sodium hydroxide, NaOH?
Na=23, O=16 and H=1 so 1 mole = (23+16+1)g ---> 40g
8 of 8

## Other cards in this set

### Card 2

#### Front

what is the realtive mass of electrons?

#### Back

almost nothing, this is why we only use the protons and neutrons when working out the mass of an atom.

### Card 3

#### Front

what is an isotope?

### Card 4

#### Front

what do we use realtive atomic masses to compare?

### Card 5

#### Front

what is the relative atomic mass?