Chemistry Yr10

Atomic number

Number of protons in nucleus

Relative atomic mass

Protons + neutrons

Amount of protons

Same as atomic number

Amount of neutrons

Mass number minus protons/atomic number

Electron amount

If neutral, same as atomic number, if not add or take charges

Isotope

Atoms of the same element with varying number of neutrons

Ions

Formed when an atom loses or gains electrons

Cation

Formed when an atom loses an electron

Anion

Formed when an atom gains an electron

Octet rule

The first 20 elements never want their valence shell to have more than 8 electrons.

Valence shell

Outermost electron shell of an atom

Metal ions are always what?

Cations

Non-metal ions are always what?

Anions

Metals want to what?

Lose electrons to get a full valence shell

Non-metals want to what?

Gain electrons to get a full valence shell

Ionic bonding

Electrons are transferred from metals to non-metals to form ions with full valence shells and become stable

Atoms with incomplete valence shells are what?

Unstable

Electron shell formula

2n² (n = shell number)

Electron shell capacities

2, 8, 18, 32

The row number

Tells you how many total shells an atom has

The column number

Tells you how many electrons are in the valence shell

Ionic lattice

Giant 3D structure formed by ionic bonding

Polyatomic atoms

Means many atoms

When writing ionic compounds…

Metals always comes first

Also when writing ionic compounds….

Simplify whole number to lowest ratio needed

How to find number of electrons in an ionised metal (cation)

Subtract number of valence electrons it had as a neutral atom from its atomic number

How to find number of shells in an ionised metal (cation)

It loses one full shell

How to find number of electrons in an ionised non-metal (anion)

Add enough electrons to the atomic number to bring the valence shell to 8

How to find number of shells in an ionised metal (cation)

Stays the same

2 steps of ionic bonding

1.Electron transfer (creating the ions)

2. Electrostatic attraction (negative and positive pull towards each other)

How is the periodic table organised

Metals, non-metals, metalloids

Metals are where?

Left side (not hydrogen)

Non-metals are where?

Right side

Metalloids are where?

Touching the staircase (not aluminium)

Properties of metals

Shiny, good conductors of heat and electricity, high density, high melting point

Properties of non-metals

Dull, poor conductors, low density, low melting point

Properties of metalloids

Between metals and non-metals

Chemical reaction

Atoms are rearranged to form new substances

Signs of a chemical reaction

Change in colour, formation of a solid (precipitate) in a solution, odour produced, change in temp, bubbles

When writing ionic equations…

Add the states of each ion

Aqueous

Dissolved in water

All nitrates are…

Soluble

When rewriting an ionic equation, if it’s aqueous

Rewrite it (expand)

When rewriting an ionic equation, if it’s solid

Leave it as is

If ions are the same on either side once rewritten (expanded)

They are spectator ions, take them out

If the ion is a soluble…

It is a solution

If the ion is insoluble…

It is a precipitate or a solid

Two colourless ions will combine to produce…

A white solid

Ionic solids…

Generally have the same colour as any coloured ion they contain

If an aqueous solution is not on the coloured ions in list…

It’s colourless

If one of the ions in an aqueous solution is on the coloured ion list…

The solution takes that colour

When observing a solid…

If the specific compound listed, use that exact colour

If the solid compound is not listed when observing…

Look up its individual ions in the aqueous solution list

If the solid isnt anywhere on the coloured ions lists…

It’s a white precipitate

When doing dissociation reactions…

The reactants will be solids, and the products will be aqueous

If there is a subscript when doing dissociation reactions…

Add the subscript in front of the ion (like balancing)

When writing dissociation reactions…

Always write the product’s charges

When writing the products of dissociation reactions…

Don’t tear apart polyatomic ions, keep them as is

Synthesis

A + B → AB

Decomposition

AB → A + B

Single displacement

A +BC → B + AC

Double displacement

AB + CD → AD + CB

Combustion

Thing being combusted + oxygen → carbon dioxide + water

Covalent compounds

Formed when non-metal atoms react

Covalent compounds are held together by…

Sharing of electrons

Naming covalent compounds when a molecule contains more than one atom of one type

mono, di, tri, tetra, penta, hexa (1, 2, 3, 4, 5, 6)

Also when naming covalent compounds…

The second part of the name is given the suffix ‘ide’

Acid + metal →

Salt + hydrogen

Acid + metal hydroxide →

Salt + water

Acid + metal oxide →

Salt + water

Acid + metal hydrogencarbonate →

Carbon dioxide + salt + water

Acid + metal carbonate →

Carbon dioxide + salt + water

Acid + base →

Salt + water (neutralisation)

Salt is formed by…

The part of an acid that isn’t the H and the part of the base that IS the metal

Arrhenius acid definition

Any substance that ionises in water to increase the concentration of hydrogen ions

Arrhenius bass definition

Any substance that ionises in water to increase the concentration of hydroxide ions

Properties of an acid

Sour taste, ph level less than 7, turns blue litmus paper red, conducts electricity

Properties of a base

Bitter taste, slippery, ph level greater than 7, conducts electricity, turns red litmus paper blue

How to use standard reduction potential series

Left hand on metal ion (side with charges), right hand on metal. If left hand is above right hand, reaction will occur.

When trying to find an unknown metal, and it reacts with all testers, it’s most likely

When trying to find an unknown metal, and it reacts with some testers, it’s most likely

When trying to find an unknown metal, and it reacts with none of the testers, it’s most likely…

Ammonium

NH4+

Bromide

Br-

Chloride

Cl-

Hydride

H-

Ethanoate/acetate

CH3COO-

Fluoride

F-

Hydrogencarbonate/bicarbonate

HCO3^-

Phosphate

PO4³-

Hydroxide

OH-

Iodide

I-

Nitrate

NO3^-

Nitrate

NO3^-

Nitride

N³-

Sulfide

S²-

Oxide

O²-

Oxide

O²-

Phosphide

P³-

Water

H2O