Atomic Structure and the Periodic Table

Because they already have a full outer shell.

He grouped elements based on their chemical and physical properties

The ‘Law of Octaves’ - Elements listed in order of atomic weight, in rows of 7 elements.

He noticed a repeating pattern ofproperties every 8th elements.However, the pattern didn't workafter a few rows and his ideaswere never accepted.

He noticed a repeating pattern of properties every 8th elements. However, the pattern didn't work after a few rows and his ideas were never accepted.

He insisted elements were grouped using properties, this created gaps. They were later discovered and his predictionswere correct. His table was accepted

Increasing Atomic Number

melting point decreases down the group, atomic radius increases down the group

Metal Oxide

Metal Chloride

Metal Hydroxide + Hydrogen

They lose their outer shell

Potassium has more electron shells than lithium. In potassium,the outer shell electron is further from the nucleus, less attracted to the nucleus so more easily lost.

Reactivity decreases down thegroup

Fluorine has fewer electron shells than chlorine. The outer shell electrons in fluorine are closer to the nucleus, more attracted tothe nucleus and are gained more easily

They form a halide ion, e.gchloride, bromide, fluoride.

A more reactive halogen can displace a less reactive halogen from its compound

As they are unreactive and gases.

They are colourless gases and they are monatomic (exist as single atoms)

Relative mass increases down the group, this causes boiling points to also increase down the group.

Because they have a full outer shell and do not need to lose / gain / share electrons

(mass x abundance) + (mass x abundance) all divided by total abundance

Number of protons

Isotopes of an element are atoms that have the same number of protons, but different number of neutrons.

Two or more different types of atom, chemically bonded together

Two or more different substances not chemically bonded together

The elements have their own properties, the atoms can be in any ratio, it isn’t easy to separate the elements as the atoms are not bonded to each other

Filtration, Distillation, Chromotography, Seperating Funnel, Fractional Distillation and Crystallisation

1. It has own unique properties that are different to the elements.

2. The formula is fixed with atoms in fixed ratios.

3. It is very hard to separate the elements as the atoms are bonded to each other.

Thermal decomposition and Electrical decomposition (electrolysis)

1. Separates a dissolved solid from the solvent it is dissolved in.

2. Mixture is heated to boil off some of the solvent, creating a hot, saturated solution.

3. As it cools the solute becomes less soluble and cannot remain dissolved.

4. Some of the solutes crystallises out of the solution as crystals.

5. The crystals can be separated from the rest of the solution by filtration.

1. Separates solvent from a solution.

2. Mixture is heated and solvent boils.

3. Solvent passes through condenser where it cools and condenses.

4. Condenser directs the solvent into a container away from original solution.

1. Liquids form two layers and bottom layer is removed using the tap at the bottom of the funnel.

2. Liquid with the greater density is the lower layer

Atoms of different elements are different sizes / masses

The 'Plum Pudding’ Model - a solid sphere of positive charge with small negatively charged electrons embedded in the surface

The ‘Nuclear’ Model - Obtained from the alpha scattering experiment

Alpha particles were fired at a gold foil a few atoms thick and obversed where they went 

Most of them went straight through and a few of them were swirvy. 1in 8000 particles bounced back of the leaf.

Most of the atom is empty space and all of the mass is concentrated on the nucleus which is very small.

Electrons live in different energy levels. These electrons can move to higher levels by absorbing electromagnetic radiation (light) or can move to lower levels by emitting light.

Discovered neutrons, and used to explain isotopes

Atoms are around 0.1nm in radius