Edexcel GCSE Chemistry Topic 1 Key concepts in chemistry overview quiz quiz

$+1$

$0$

$-1$

$+2$

The number of protons in the nucleus only

The total number of electrons in the atom

The number of neutrons in the nucleus only

The number of protons plus neutrons

Atoms of the same element with different numbers of neutrons

Atoms of different elements that all share the same mass number

Atoms of the same element with different numbers of protons

Charged atoms that have lost or gained electrons

$24.0$

$24.3$

$25.0$

$26.0$

Group 8, period 1

Group 3, period 1

Group 1, period 3

Group 1, period 2

The ions chemically react with the electrodes only once the compound has been fully melted

Solid sodium chloride contains no charged ions at all

Melting the compound adds extra electrons to its structure

When molten the ions are free to move and carry charge, but when solid they are fixed

Diamond has four bonds per carbon and graphite has three plus a delocalised electron

Both diamond and graphite conduct electricity equally well in every single direction

Graphite is much harder than diamond and is used in cutting tools

Diamond has delocalised electrons that let it conduct electricity

The positive metal ions move freely through the whole structure

Delocalised electrons are free to move and carry charge

Metals are made of small separate molecules

Metals contain free protons that carry the charge

$68$

$84$

$100$

$116$

$CH$

$CH_4$

$C_2H$

$CH_2$

$40$ g/dm$^3$

$4$ g/dm$^3$

$16$ g/dm$^3$

$1600$ g/dm$^3$

Extra mass is always created during chemical reactions in a flask

No atoms are made or destroyed and none can enter or leave

Any gases produced are destroyed inside the sealed flask

The reaction simply stops happening once the flask is sealed

John Dalton, the chemist

J. J. Thomson, the physicist

Ernest Rutherford

James Chadwick