C1 - Elements

Question 1

What is an element?

Answer 1

A pure substance that cannot be broken down

(They all have the same number of protons in their nucleus)

Question 2

How can you determine what type of atom it is?

Answer 2

The number of protons

(For example an atom with one proton in its nucleus is hydrogen and an atom with two protons is helium)

Question 3

How many elements are there?

Answer 3

About 100 (118 in modern today)

Question 4

How can atoms be presented as a shortcut

Answer 4

By a one or two letter symbol - this saves you writing out the full name of the element.You usually see these symbols on the periodic table

(For example oxygen would be O)

Question 5

What do isotopes have in common with elements

Answer 5

The same atomic number BUT different mass numbers

Question 6

Why is an average mass made for the relative atomic mass SPECIFICALLY for isoptopes?

Answer 6

As many elements can exist as a number of different isotopes,an average mass is made taking into account the different masses and abundances(amounts) of all the isotopes that make up the element

Question 7

State an example of a pair of isotopes

Answer 7

Carbon-12 and Carbon-13

Question 8

What is the formula to work out the relative atomic mass of an element?

Answer 8

RELATIVE sum of (isotope abundance x isotope mass number)
ATOMIC = ——————————————————————————-
MASS (Ar) sum of abundances of all the isotopes

Question 9

Copper has two stable isotopes.Cu-63 has an abundance of 69.2% and Cu-65 has an abundance of 30.8%. Calculate the relative atomic mass of copper to 1 decimal place.

Answer 9

1) (69.2 x 63) + (30.8 x 65) 4359.6 + 2002
———————————– = —————————
69.2+30.8 100

2) 6361
———— = 63.616
100

3) To 1 decimal place so 63.6