Chemistry Term 1 Knowledge Flashcards
What is an atom?
The smallest unit of matter, contains sub-atomic particles such as electrons (- charge), protons (+ charge) and neutrons (0 charge).
What are ions and what are their types?
Ions - charged atoms
Cations - positive charged atoms
Anions - negative charged atoms
What is mass number?
Represented by A, the atomic mass is the amount of matter in the atom, equal to the number of protons + neutrons.
What is atomic number?
Represented by Z, it symbolises the number of protons in the nucleus of atom.
What are isotopes?
Atoms of the same element and same number of protons that have different number of neutrons to protons which make them radioactive, also known as radioisotopes.
What is a molecule?
Two atoms of the same/different elements bonded together.
What is electrostatic attraction?
A non-contact force attracting positive subatomic particles to negative ones.
What are the periods and groups.
There are 7 periods in the periodic table that go horizontally and 8/18 groups that go vertically.
What are the specific types of elements?
Alkali metals
Alkaline earth metals
Transitional metals
Halogens
Noble gases
Rare earth metals
What are Isotopes?
Atoms of the same element that have the same number of protons but different number of neutrons.
Stoichiometry
Branch of chemistry which utilised relationships between products and/or reactants in a chemical reaction to determine desired quantitative data.
How do you convert grams of substance A to grams of Substance B?
Grams A => mol A => mol B => grams B
How do you convert moles of substance A to moles of Substance B?
Moles A => Moles B
Law of conservation of mass
In a chemical reaction, mass can neither be created nor destroyed.
Types of reactions.
- Combination or synthesis.
- Decomposition
- Single replacement/displacement
- Double replacement/displacement
- Combustion
- Precipitation
- Neutralisation (acid/base)
Combination reaction
Reaction where 2 or more reactants combine to form a single product (which must be compound)
Decomposition/decombination
Single reactant breaks down into multiple products.
Single replacement/displacement
One element in compound is replaced by another element.
Double displacement/replacement
Cations and anions swap partners to form compounds.
Neutralisation
Reaction between acid and base and always produces salt and water and sometimes gas.
Combustion
Reaction where O2 reacts with reactants and/or it produces H2O and CO2. General FORMULA: CyHx + O2 = CO2 + H2O
Precipitation
Double replacement reaction where one of new substances is insoluble, which is a solid also known as precipitate). GENERAL FORMULA: AB(aq) + CD(aq) => AD(s) + CB(aq)
What are the diatomic elements?
- Bromine (Br)
- Iodine (I)
- Nitrogen (N)
- Chlorine (Cl)
- Hydrogen (H)
- Oxygen (O)
- Fluorine (F)
Oxidation rules
- Element by itself has ON of 0
- Group 1A has always a +1
- Group 2A has always a +2
- Halogens usually have -1 but have a positive ON when with oxygen.
- Sum of ON’s for neutral compound =0
- Sum of ON’s for a polyatomic ion = Ionic charge of ion
- monoatomic ion has ON=ionic charge
- Oxygen is usually -2 but -1 in peroxide
General formula for peroxides
A2O2, with A representing a metal or a non-metal.
Indications that a compound is a peroxide
If it contain 2 oxygen atoms.
Electronegativity
The measure of an atoms ability to attract electrons towards itself when it forms a chemical bond.
