Chemistry - year 10 - igcse

Why does an atom have an overall charge of zero?

Since neutrons have no charge and the protons and electrons have the same amount of charge they cancel out.

What is the mass number?

Larger number and its the amount of protons + neutrons

What is the atomic number?

The number on the bottom of the element. Number of protons = the number of electrons

Define isotope

Atoms of the same elements with the same number of protons but a different number of neutrons

How do you find the relative atomic mass?

Take the mass and multiply it by the abundance. Add them together and divide by 100

What is group 1?

Alkali Metals

What is group 7?

Hallogens

What is group 0?

Noble gases

Define delocalised electrons

Electrons in the outer shell of metals. They move through the structure carrying a charge

What is an ion?

A charged substance formed when it had lost or gained electrons

What does the number of electrons in the outer shell mean?

Tell us the group number

What does the number of shells tell us?

The period the element is in

Define ionic bonding

Transfer of electrons between metals and non metals, also the electrostatic attraction between positive and negative ions

What is the charge of ammonium? NH4+

1+

What is the charge of potasium?

1+

What is the charge of sodium?

1+

What is the charge of zinc?

2+

What is the charge of calcium?

2+

What is the charge of magnesium?

2+

What is the charge of copper?

2+

What is the charge of iron(II)?

2+

What is the charge of Iron(III)

3+

What is the charge of lead?

2+

What is the charge of chloride?

1-

What is the charge of bromide?

1-

What is the charge of iodide?

1-

What is the charge of hydroxide?

1-

What is the charge of nitrate?

1-

What is the charge of oxide?

2-

What is the charge of carbonate?

2-

What is the charge of sulfate?

2-

What is the charge of sulfide?

2-

What is the charge for nitrate?

3-

What is covalent bonding?

The electrostatic attraction between the nucleus of both atoms and the shared pairs of electrons

What are the two different types of covalent bonding?

Simple molecular - low melting + boiling point

Giant covalent - Graphite, diamond, silicone dioxide

What is an allotrope?

Different forms of the same element

Name the properties of diamond

High melting point and high thermal conductivity

What is the structure of diamond?

Giant covalent structure where each carbon atom is covalently bonded to four other carbon atoms forming a 3D tetrahedral network with strong bonds

What are intermolecular forces?

They are forces of attraction which we heat

What are the different types of metalic bonding?

Giant metalic latice

Why is diamond hard and have a high melting point?

The strong covalent lattice found in diamond makes is hard and makes it have a high melting point (over 4000 c)

Why cannot diamond conduct electricity?

It has no delocalised electrons so it cannot conduct electricity

Why is graphite soft?

Each carbon atom is bonded to 3 other carbon atoms this creates layers of carbon atoms which can slide over each other making graphite soft. Also it has weak intermolecular forces between each layers.

What is C60 Fallerine?

Another allotrope of carbon which is a simple molecular substance held together by intermolecular forces. It does not conduct electricity and it has a large surface area.

Define metalic bonding

The electrostatic attraction between the positive metal ions and the delocalised electrons

What is the structure of a metal?

Giant metalic latice

How are metal ions arranged?

In regular layers, one on top of another

What are the electrons called in metallic bonding?

They are called a "sea" of delocalised electrons which can move freely around the structure which explain the characteristics of metals

Why do metals have high melting and boiling points?

The electrostatic attraction is very strong so it takes a lot of energy to break them.

Why are metals malleable?

They have layers of ions that are able to slide over each other

What happens when there is an increased amount of shells?

The distance from the nucleus increases so there is less force of attraction between the outer shell electrons and the nucleus. The weaker the attraction the easier it is for the outer shell electrons to be lost.

Define displacement reaction

A reaction which a more reactive element displaces a less reactive element

what is the density, arrangement of particles, movement of particles and energy of particles in a solid?

High density, regular pattern, vibrate around a fixed position and low energy

what is the density, arrangement of particles, movement of particles and energy of particles in a liquid?

Medium density, randomly arranged, move around each other and greater energy

what is the density, arrangement of particles, movement of particles and energy of particles in a

Low density, randomly arranged, move in all directions and highest energy

Define diffusion

The movement of particles from an area of high concentration to low concentration

How do you speed up diffusion?

Use hot water and stir the mixture

Define mixture

Two or more types of atoms which are bonded

True of false pure substances boil at a fixed tempurature

True - water at 100C

Define solvent

The liquid used to dissolve

Define solution

A solute dissolved in a solvent

Define solute

The substance that is dissolved

Define saturated solution

The maximum amount of solute that can dissolve in a particular volume of solvent

What does crystalisation do?

Used to separate a soluble solid from a solution and its used to produce solid crystals from a solution

What does filtration do?

Used to separate some mixtures and they let smaller pieces or liquids through but trap larger pieces

Define simple distilation

The method of separating a solvent from a solution

Define fractional distilation

The method of separating mixtures of liquids from a solution

What is a cromatagram?

The composition of a mixture, the more soluble the ink/dye is the further it will travel

How do you calculate the rf?

distance spot moved divided by distance solvent moved

Name the gasses in the atmosphere and the percentages

Nitrogen 78%, Carbon dioxide 0.04%, oxygen 21% and argon <1% or 0.9%

How do you calculate the % of oxygen?

change in volume over total volume multiplied by 100

What is the avagadro constant?

6.02 x10 to the power of 23

How do you calculate moles?

moles = mass over mr

How do you calculate the percentage yeild?

actual yeild over theoretical yeild multiplied by 100

How to calculate concentration?

Moles over volumes

How do you calculate volume?

Moles x 24

What is the reactivity series list?

Potassium, sodium, lithium, calcium, magnesium, aluminium, carbon, zinc, iron, hydrogen, copper, silver, gold

How do you name salts?

1) name of the metal goes first

2) Acid udes

What do you call hydrocloric acid if it was used in salt?

Chloride

What do you call nitric acid if it was used in salt?

Nitrate

What do you call sulfuric acid if it was used in salt?

Sulfate

Why does iron rust?

The process of oxidisation occurs when iron is exposed to moisture and oxygen. This gradually corodes the metal

How does the barrier method prevent rusting?

It creates a physical barrier between the iron and oxygen and moisture. You can use paint or oil and grease

What is galvinising?

Zinc is used to coat the iron and prevent it from rusting

How does the sacrificial method prevent iron from rusting?

It coats the iron in a more reactive metal so that metal reacts with oxygen instead of iron

What does boiled water not have?

Boiled water does not have oxygen

What is oxidisation?

When a substance gains oxygen

What is reduction?

The loss of oxygen in a substance

What is a redox reaction?

A reaction in which one substance is oxidised and one substance is reduced

What is the oxidising angent?

Causes another substance to become oxidised

What is the reducing agent?

Causes another substance to be reduced

What does a half equasion show?

The gain or loss of electrons

What are two methods to extract metals?

Using carbon and electrolysis

Why can carbon only be used to extract some metals?

Carbon can only be used on metals that are lower on the reactivity scale

Why is carbon dioxide sometimes formed during electrolysis?

Because electodes are mostly made of carbon/graphite so if oxygen is formed during the process the oxygen will react with the carbon and form carbon dioxide

What does the cathode attract?

The cathode attracts positive

What does the anode attract?

The anode attracts negative

If there is a halide ion present at the anode what will be formed?

Oxygen will be formed