1.15 deduce the number of outer electrons in a main group element from its position in the Periodic Table.

Explained in 1.14, but here we go again:

NUMBER OF OUTER ELECTRONS:

- Number of outer electrons can be found by what group it is in. (Down).
- Number of shells can be found by what period it is in. (Across).

1.14 deduce the electronic configurations of the first 20 elements from their positions in the Periodic Table

ELECTRONIC CONFIGURATIONS:

- Elements in the same group have the same number of outer shell electrons.
- Elements in the same period have the same number of shells.
- Only a certain number of electrons on each shell are allowed:
1st Shell = 2
2nd Shell = 8
3rd Shell = 8

- E.g. Boron, 2nd period which means 2 shells, and 3rd group which means last shell has 3 electrons.
- Boron = 2.3

1.13 understand that the Periodic Table is an arrangement of elements in order of atomic number

PERIODIC TABLE:

- The periodic table is always in order of atomic number.
- Increasing atomic number.
- Atomic number equal to amount of electrons each atom has.

1.12 calculate the relative atomic mass of an element from the relative abundances of its isotopes

RELATIVE ATOMIC MASS (Ar):

- Calculated by (% of the isotope x the relative abundance) + (% of the isotope x the relative abundance) / 100

- Chlorine:
Atomic mass = 35 + 37
Abundance = 3 + 1
- Therefore 2 isotopes of chlorine (Cl); (³⁵Cl) and (³⁷Cl).
- The abundance shows that for every 3 atoms of (³⁵Cl), there is 1 atom of (³⁷Cl).
- So now you multiply the relative atomic mass by its abundances.
- Add them together.
- Divide them by the total amount of abundances.

- (35 x 3) + (37 x 1) / (3 + 1)
- = 35.5

1.11 understand the terms atomic number, mass number, isotopes and relative atomic mass (Ar)

ATOMIC NUMBER:

- Is the total number of protons in the nucleus of an atom.

MASS NUMBER:

- Is the total number of protons and neutrons in the nucleus of an atom.

ISOTOPES:

- Are the different forms of the same element. They have the same amount of protons but different amounts of neutrons. For example:
Carbon-12 has 6 protons, 6 electrons, and 6 neutrons
Carbon-14 which has 6 protons, 6 electrons, and 8 neutrons.

RELATIVE ATOMIC MASS (Ar):

- It is the measure of the mass of one atom of the element. Basically it is how heavy different atoms are based on the scale of an atom of carbon-12.
- It is the average mass of all isotopes of an element.
- To calculate it:
1. Write the formula.
2. Write how many of each atom.
3. Write in relative atomic mass(Ar) for each type of atom.
4. Calculate the total mass for each element.
5. Add up total mass for the compound.

1.10 recall the relative mass and relative charge of a proton, neutron and electron

RELATIVE MASS:

- Proton = 1
- Neutron = 1
- Electron = 1/1840

RELATIVE CHARGE:

- Proton = +1
- Neutron = 0
- Electron = -1

1.9 understand that atoms consist of a central nucleus, composed of protons and neutrons, surrounded by electrons, orbiting in shells

We went over this in 1.5 but here we go again:

STRUCTURE:

- The nucleus consists of protons and neutrons. On the outside of the nucleus are the electron shell(s) which consist only of electrons.