Chemistry Unit 1 QCAA

What is the atomic number

number of protons or electrons

What is the atomic mass

Neutrons + protons

How to find number of neutrons

Atomic mass-atomic number

Symbol for atomic mass

A

symbol for atomic number

z

What is a isotope?

An element with a different amount of neutrons

Energy shell def

The different distances from the nucleus the electrons orbit in

Electron configuration def

The distribution of the electrons in orbitals around the nuclei

Valence electron def

The outermost electron that determines chemical properties and reactions

Maximum amount of electrons in orbital formula

2n^2 n being energy level

What are the different subshells and what is their capacity

s\=2,p\=6,d\=10,f\=14

What is Aufbau's principle for electron configuration?

Electrons fill orbitals from the lowest energy level to the highest energy level going upwards

What is Pauli exclusion principle

No more than two electrons can fit in the same orbit. They must be different spins as well.

What is Hund's rule

When filling the energy levels we fill with one until equal energy then go back and fill again

Electron configuration order

1s,2s,2p,3s,3p,4s,3d,3p,5s,4d,

How to write electron config with noble gas

Use closest noble gas then write the rest of the subshells

What is the relative atomic mass

The average atomic mass of all the elements in the universe

What is the name of group 1

alkali metals

What is the name of group 2

alkaline earth metals

Atomic radius trends

decrease across the periods and increase down the groups because of the added levels and they repel

Is the atomic radii for anion larger or smaller than cation

Cation - smaller (positive pulling in)
Anion - Larger (larger as repelling)

What is the first ionization energy

The energy required to remove an electron

Ionisation energy trends

Ionisation energy increases across periods due to nuclear charge and decreasing going down because of shielding and further away

Electronegativity def

The ability to attract a pair of electrons in a covalent bond to itself

Electronegativity trends

Increases across period because of higher nuclear charge to attract and decreases down a group because shielding decreases the charge

Chemical bonding Def

A chemical bond is an attraction between atoms that allows the formation of a chemical substance

How can you represent bonding

Lewis dot diagrams (showing valence electrons)

What are the different types of bonding

Metallic - Metals bonding
Ionic - Transfer from metal to non metal and cations and anions form
Covalent - Two non-metals join and share electrons

What is an Ion

An atom where the amount of electrons are not equal to the amount of protons

Monatomic ions def

Ions that have one element and have no charge

Polyatomic Ions

ions that have 2 or more atoms with a charge

How does ionic bonding work?

Chemical bonding that involves the transfer of electrons to another atom which creates an electrostatic attraction (between + and ) to the meet and bond

How do you know if something is a ion

If it ends in ide

What is a ionic lattice?

Anions form framework and cations fill in the space

Properties of ionic substances

1. solid at room temp
2. High melting points
3. as solids they don't conduct electricity but as molten or aqueous they do
4. brittle
5. hard

What is covalent bonding?

when atoms share one or more pairs of electrons

What is covalency

The number of electrons shared when bonding to create a full outer shell (e.g single bond, double bond, triple bond)

What is a diatomic molecule?

a molecule that contains two atoms (Oxygen, Nitrogen, Chlorine)

What are the different prefix's for covalent bonding

Mono, Di, Tri, Tetra, Penta, Hexa, Hepta, Octa , Nona, Deca

What are the two ways to show covalent bonding

Lewis dot diagrams, valence structure

What shape does two electron pairs make

Linear

What shape does two electron pairs with double bonds

Linear

What shape does three electron pairs make

Trigonal planar

What shape does 2 bonding and 1 non bonding make

Bent shape

What shape does 4 electron pairs make

Tetrahedral

What shape does three bonding and one non bonding

Pyramidal shape

What shape does two bonding atoms and 2 lone pairs make

Bent

What are the 2 types of matter

pure substances (made of 1 particle that have the same properties) and mixtures (2 or more particles that have different properties (salt and water))

What are the 2 types of pure substances

Elements (1 atom that cannot break down) ,Compound (can break down, behave the same)

What are the 2 types of mixtures

heterogeneous (2 or more substances that cannot breakdown) and homogeneous ( substances that look the same but when tested have different properties)

What are the heterogenous types of separation

Filtration, seprating funnels

What are the types of homogenous separation

Distillation, Evaporation

What is metallic bonding?

the chemical bonding that results from the attraction between metal cations and the surrounding sea of electrons

What is a metal alloy?

A mixture of two or more metals from metallic bonding

What makes a weak metallic bond

A element such as Na which only gives only 1 electron to the electron cloud

properties of metallic bonds

as a solid conduct energy, malleable, ductile , lustrous

What determines how atoms fit together

Size of the metal atom, distance between the nuclei, the outlying electrons

What does aq mean

aqueous (dissolved in water)

What is a combination reaction

A + B --\> AB
2 separate to 1 compound

What is a decomposition reaction?

AB --\> A + B
Compound to broken down

What is a precipitation reaction?

Where two solutions react and an insoluble solid (precipitate) is made

What is a Neutralisation reaction?

acid + base \= salt + water

What is a combustion reaction?

Oxygen with compound \= Carbon dioxide and water (give off heat)

What is a Displacement reaction

A + BC \= AC + B

What does an acid + metal make

salt + hydrogen

What does acid + carbonate make

salt + carbon dioxide + water

What are the diatomic molecules

hydrogen, nitrogen, fluorine,oxygen, iodine, chlorine, bromine,

What does is hydrochloric acids, sulfuric acid and nitric acid

HCl
H2SO4
HNo3

What are the polyatomic ions that end don't end in ate or ite

Cyanide
Hydroxide
peroxide

What is Avogadro's number?

6.022 x 10^23 the mole

What is the symbol for moles

n (mol \= unit)

what is molar mass

the mass of one mole of a substance

How to find molar mass

the relative atomic mass

How to find molar mass of compound

Sum of
How many there are in compound x atomic mass

How to calculate moles

mass/molar mass

Steps to finding mass

write balanced equation
write mole calculation
work out how many moles are in the substance
rewrite mole ratio
Calculate mass \= mole x molar mass

Percentage composition

mass of element/mass of compound x 100

Empirical formula steps

Find mole ratio and then the closest whole number ratio (divide smallest number by the others). Then write. (moles become smallest number)

Molecular formula steps

1. empirical formula
2. Empirical mass (molar mass of empirical formula)
3. Find factor ratio (mol of compound/molar mass of empirical formula)
4. times factor by empirical formula (MOLECULAR FORMULA)

What is an empirical formula?

The empirical formula gives the smallest whole number ratio of atoms in a compound.

limiting reagent/reactant

any reactant that is used up first in a chemical reaction

what is a theoretical yield

max amount of product that can be produced

What is a reaction yield

amount actually produced throughout the experiment

how to calculate percentage yield

reaction yield/theoretical yield x 100

define energy

the capacity to do or supply work

What is side potential chemical energy

energy stored from a chemical reaction

Why does a breaking down reaction require energy

takes energy to break down and energy is released as the chemical bonds form

How does heat flow

Warm to cold

What is heat

When energy is transferred from 1 object to another due to temp difference

How is heat measured?

calories or joules

how are degrees Celsius and kelvins related

Go up in the same increments

heat capacity definition

The amount of energy (Joules or Calories) a system must absorb to give a unit change in temperature. (Celsius or kelvin)

heat formula

q\=mcΔT

Enthalpy

The heat content of a system at constant pressure

Exothermic reaction in terms to enthalpy

negative, products contain less energy than reactants, energy is around the reaction

Endothermic in terms to enthalpy

positive, products contain more energy than reactant, heat is absorbed by reaction

Types of Bond energies

endothermic - breaking chemical bonds which requires energy
exothermic - form new chemical bonds releasing energy

Bond enthalpy table facts

average energy it takes to break bonds and the amount of energy should double although it doesn't it almost double because the amount of energy each time gets weaker

Steps to find bonds enthalpy

Bonds broken (reactants)
- Find bonds and bond energy (if number in from then times by the bond energy by the beginning number)
- Plus values
Bonds formed (Product)
- Big number x little number
- this value x bond energy
Bonds broken-bonds formed

What is calorimetry?

way to measure heat transfer through experimental techniques