ATOMIC STRUCTURE & PERIODICITY
The last subatomic particle that was discovered was
neutron
Bond formed when two atoms share a pair of electrons.
covalent bonding
Name the homologous series with general formula CₙH₂ₙ₊₂.
alkanes
A reaction that releases heat.
exothermic
Give the chemical formula of Chromium(III) chloride
CrCl3
The number of protons in an atom is also known as the ________.
atomic number
The region of space where an electron is most likely found.
orbital
The process of breaking a large hydrocarbon into smaller molecules.
cracking
Give one reason why increasing surface area speeds up reactions.
More particles exposed / more frequent collisions.
Give the chemical formula of Sodium carbonate
Na2CO3
The most stable electron configuration is achieved when atoms have a full outer shell, governed by what principle or rule?
octet rule
Element X has atomic number 17. How many electrons are in its third shell?
7
The functional group present in alcohols.
OH
Reason why food spoils faster at room temperature than in a refrigerator.
Higher temperature increases reaction rates / bacterial activity.
Give the chemical formula of Potassium phosphate
K3PO4
Across a period, ionisation energy generally increases. Give the reason.
increasing nuclear charge
Explain why chlorine is more reactive than bromine.
smaller atomic radius and stronger attraction for electrons?
Explain why alkenes are more reactive than alkanes.
the presence of a C=C double bond
Why does a strong acid fully ionize in water but a weak acid does not?
Strong acids have a higher tendency to donate protons, while weak acids only partially dissociate
Give the chemical formula of zinc nitrate
Zn(NO3)2
Name the group of elements that doesnt follow the main group rulings
transition elements
Why are alloys stronger than pure metals?
Different-sized atoms disrupt the layers, preventing them from sliding.
Two compounds with the same molecular formula but different structures.
isomers
Explain how catalytic converters reduce air pollution.
They provide a surface for redox reactions that convert harmful gases (CO, NOx) into less harmful ones (CO₂, N₂).
Give the chemical formula of ammonium sulfate
(NH4)2SO4