3U Chemistry

Periodic trends

Atomic Radius

The distance from the middle of the nucleus to the outermost shell. As the energy levels increase the radius does too

Electron Affinity

When an atom can attract bonded electrons

First Ionization Energy

The energy required to move one of the loosely held electrons from the gaseous atom

Element Properties

Periodic table groups

alkali metals, alkaline earth metals, transition metals, metalloids, other metals, non metals, halogens, noble gases and rare earth elements

Atomic number is the amount of electrons and protons

atomic weight is the number off neutrons

Kinetic Molecular Theory

Particles of gas are in constant motion and collide with one another

Gas is mostly empty space

Pressure is exerted when particles hit the sides of the container while causing collisions

We assume that particles do not interact with each other

Average kinetic energy is proportional to the temperature

Gas Law

Boyle's Law

States that pressure and volume are inversely proportional as the temperature and mass remain constant

Charle's Law

States that temperature and volume are directly proportional as long as mass and pressure remain constant

Gay-Lussak's Law

States that temperature and pressure are directly proportional while the volume remains constant

Gas stoichiometry

Ideal Gas Law

PV=nRT

STP and SATP

The relationship between the relative quantities of the reactants in a reaction.

Calculated using mole to mole ratio, mass, volume, concentration, molar mass

Limiting and access reactants

Limiting Reactant

A reactant that is completely consumed during a chemical reaction

Access Reactant

A reactant that remains after the reaction is complete

Titrations

Used to determine the concentration of a solution

Acids and Bases

Acids

With a PH less than 7, an acid is a molecule or ion capable of contributing a proton or, alternatively, forming a covalent bond with an electron pair.

Bronsted-Lowry theory, Arrhenius theory

Bases

A base is a substance with a PH greater than 7 that can neutralise an acid by reacting with hydrogen ions.

PH scale

it tells us how basic or acidic the solution is.

Intermolecular forces

Occurs between molecules

London Dispersion

Polar and non-polar molecules form temporary bonds by the constant movement of electrons causing a short-term charge imbalance

Dipole-Dipole

Polar molecules only are held together due to their partial charges

Hydrogen Bonding

Polar molecules but a hydrogen has to be bonded to a F, O, N

Intramolecular Forces

Occur within the molecule

Covalent

sharing of electrons between two non-metals

ionic

the transfer of one or more electrons between a metal and non-metal

Chemical Bonding and Electronegativity

Electronegativity is When an atom is bonded, it has the potential to draw individual electrons to itself.

Non-polar covalent bonds

Polar covalent bonds

Ionic bonds

Lewis Structures and VSEPR Diagrams

Lewis structures show which atoms are bonded together in a molecule

types of reactions

Synthesis ( A+B=AB)

Decomposition (AB=A+B)

Single displacement (A+BC=AC+B)

Double displacement ( AB+CD=AD+CB)

Combustion (C2H2+O2=H2O+CO2)

can also be incomplete

Writing Chemical Equations

Balancing equations

To even out the amount of an element on the other side of the reaction

Activity series

a list of decreasing order of their reactivity

Solubility rules

shows you which elements are insoluble