Atoms, Ions And Compounds. Flashcards
Relative formula mass.
The weighted mean mass of the formula unit of a compound compres with 1/12th of the mass of an atom of carbon-12.
Isotope definition.
Atoms of the same element with different numbers of neutrons and different masses & same numbers of protons.
Relative isotopic mass.
The mass of an atom of an isotope compared with 1/12th of the mass of an atom of carbon-12.
Relative atomic mass (Ar).
The weighted mean mass of an atom of an element compared with 1/12th of the mass of an atom of carbon-12.
Calculating relative atomic mass (Ar).
Ar=Sum of isotopic mass x abundance/ sum of all substances.
Relative molecular mass (Mr).
The weighted mean mass of a molecule of a compound compared with 1/12th of the mass of an atom carbon-12.
Relative mass of electrons, neutrons and protons.
Electron: 1/1836.
Neutron: 1 (Slightly greater than a proton).
Proton: 1.
Most mass is in the nucleus.
Relative charge of subatomic particles.
Proton: Positive charge (1+).
Electron: Negative charge (1-).
Neutron: Neutral/ no charge.
Charge of proton is equal to charge of electron but opposite.
Overall charge of nucleus=0.
Mass number.
Protons + neutrons.
Atomic number.
Protons/electrons.
Neutron.
Atomic number - mass number.
Ions.
Number of electrons different from number of protons.
Cations (positive ions)- less electrons than protons.
Anions (negative ions)- more electrons than protons.
Negative charge=gained electrons.
Positive charge=lost electrons.
Relative formula mass/molecular mass calculation.
Number of atoms x atomic mass.
Do for all elements in molecule and add together to find relative mass.
Important ions to know.
Ag + Silver
Zn 2+ Zinc
NH4+ Ammonium
OH- Hydroxide
NO3- Nitrate
CO3 2- Carbonate
SO4 2- Sulphate
PO4 3- Phosphate.
Ionic equations.
1) Split aqueous solutions into ions- not solids or liquids.
2) Cancel ions that are the same on both sides (but not if a solid or liquid only aq) = spectator ions.
3) Tells you which ions are actually reacting.
