Atoms were tiny spheres that could not be divided. (1805)

What did John Dalton’s experiment show?

It was a sphere of positive charge with negative charges soread throughout (1904).

Ernst Rutherford - alpha particles were fired at gold foil and they scattered and this meant the mass of an atom was concentrated in a nucleus. It states electrons orbited around the nucleus (1909).

Niels Bohr - he noticed that the light given out when atoms were heated only had specific amounts of energy so he thought the electrons orbited at fixed distances (1914).

James Chadwick - an experiment with alpha particles and a radiation was given off. This radiation was interpreted as being composed of particles with a neutral electrical charge and the approximate mass of a proton (1932).

What is the mass of protons, neutrons and electrons?

Protons: positive, Neutrons: neutral and Electrons: negative

What is the charge of protons, neutrons and electrons?

What does the relative atomic mass number tell you?

Atoms with the same number of protons but a different number of neutrons. Atoms of the same element with the same atomic number but a different mass number.

How many electrons are found in the first 3 shells?

The group number tells you the number of electrons on the outer shell.

What is the link between the group number and the electronic structure?

The period number tells you how many shells are in the electronic structure.

What is the link between the period number and the electronic structure?

It explains the chemical properties of an element. Elements with similar configurations react in similar ways.

What does the electrons configuration tell you?

The alkali metals become more reactive down the group but the melting and boiling points decrease as you move down.

What is the trend in reactivity for group 1?

Good conductor of electricity and heat, shiny, malleable, ductile and high melting/boiling points.

They are useful for circuits, wires and jewellery too as it can be polished.

They are unstable as they do not have a full outer shell so the lose it after the reaction to make it stable.

Why do alkali metals lose the outer electron after they’ve reacted with water?

The inner shells cause the outer shell to be further away and the further away the outer electron is, the weaker it’s attraction is to the nucleus - easier to lose it.

The halogens get less reactive as you go down the group but the melting and boiling points increase as you move down.

What is the trend in reactivity for group 7?

Aluminium iodide - has purple vapour and a flame.

You multiply each element in the compound by how many atoms there are and each ones mass.

How do you calculate the relative formula mass?

What do you see when lithium reacts with water?

It burns in a ball, heat of reaction is enough to melt it, sometimes catches fire and releases hydrogen.

What do you see when sodium reacts with water?

Lilac flame with a spark and it’s dark blue/purple.

What do you see when potassium reacts with water?

What do alkali metals produce when they react with water?

English (UK)

Chemistry: Half-Term 1 (Y9)
-history of the atom
-compounds 
-trends in reactivity
-electronic configuration 
and more

Revision note

shakthi 🧍‍♀️😟

United Kingdom

chemistry: half-term 1 (y9)
-history of the atom
-compounds 
-trends in reactivity
-electronic configuration 
and more

atomic structure

Flashcards

Substances, Elements, and Reactions

Electronic structure of atoms (year 9/10)

GCSE AQA Chemistry paper 2

year 8 chem flashcards /questions