C2 - Atomic Structure Flashcards
What is an element?
A substances where all atoms contain the same number of protons
What are isotopes?
Variants of an element that have the same number of protons and electrons but a different number of neutrons
Why do isotopes chemically behave in the same way as each other?
Chemical reactions are determined by the number of electrons
Why are the physical properties of isotopes different?
The different numbers of neutrons will cause the masses of the different isotopes to be different
What is the atomic number?
The number of protons in the element
What is the mass number?
The total number of protons and neutrons
How do you calculate relative atomic mass?
Multiply mass number of isotope by its abundance for each isotope
Add them all together
Divide by 100
Why is the relative atomic mass of chlorine 35.5?
The 35.5 is an average
75% of chlorine is 35 and 25% is 37
What is relative atomic mass?
An average of the mass numbers of all isotopes of an element
What is relative formula mass?
A way of calculating the mass of a compound compared to other compounds and elements
How do you calculate relative formula mass?
Add together the relative atomic masses of every atom in the compound
What is a formula unit?
When calculating relative formula mass, the formula unit is the compound we are calculating the relative formula mass of
Show how would calculate the relative formula mass of water
In water, there is one oxygen and 2 hydrogens
16 + (2 * 1) = 18
The relative formula mass of water is 18
How do you work out how much 1 mole is of a substance?
1 mole is the relative atomic mass or relative formula mass in grams
If we know the relative formula mass of water is 18, how much is 1 mole of water?
18g
