Edexcel GCSE Chemistry Paper 1. Foundations Chemistry Summary Questions with Detailed Answers 2024/2025

atom - Ans .smallest particle of an element proton - Ans .- positively charged particle - has a mass of 1 and a charge of +1 - found in the nucleus of the atom. neutron - Ans .- has no charge(neutral) and a mass of 1. - found in the nucleus of an atom electron - Ans .- a negatively charged particle - has a mass 1/2000 - found in energy levels which surround the nucleus. atomic number - Ans .the number of protons and electrons atomic mass - Ans .the total number of protons and neutrons isotopes - Ans .atoms of the same element which have the same atomic number, but a different number atomic mass, because they have a different number of neutrons.- have different atomic masses formula for relative atomic mass - Ans .(Mr x abundance)+(Mr x abundance)/ 100 period number - Ans .tells you the number of electron shells group number - Ans .tells you the number of electrons, in the outer electron shell Properties of Mendeleev's periodic table - Ans .- ordered in increasing atomic mass - arranged elements into groups of similar properties - left gaps to predict properties elements yet to be discovered - only had 63 elements modern periodic table - Ans .- ordered by increasing atomic number - has over a 100 elements - categorised into groups which indicate the number of electrons in the outer shell group 1 - Ans .alkali metals group 2 - Ans .alkali earth metals group 3 - Ans .transition metals group 7 - Ans .halogens group 10 - Ans .noble gases electron configuration - Ans .2,8,8.. E.g magnesium has an atomic number of 12 so its electron configuration will be 2.8.2 metals into ions - Ans .lose electrons to become positively charged Group 1- lose 1 electron to gain a +1 charge