Year 10

More H please!Metal chemistry.

SLO’s• Name and locate various groups of elements on the periodic table.• Be able to draw the first 20 elements by using their atomic number and

mass as an indicator of their subatomic particles.• Explain how to predict what ions will be made from the first 20 elements.• Explain what an isotope it and how they are identified.• Describe the six properties that metals have in common.• Carry out the pop test for hydrogen, glowing splint test for oxygen and the

flaming splint test for carbon dioxide.• Use the rules; MOMO, MASH & MWMHH to explain how metals react with

oxygen, acid and water.• Use the “Stop, swap and drop” method of predicting the products of these

metal reactions.• Design a fair test on factors affecting reaction rates using the reaction of

calcium carbonate with acid.• Relate the findings of their experiment to collision theory and explain how

collision theory applies to temperature, concentration, surface area & catalysts

The periodic table.

• Can you remember the first 20 elements, in order, from our last Chemistry topic?

• Do you remember the periodic patterns?

• Let’s review!

Rows.

• Rows are called periods - elements have the same number of orbital shells and these a filled progressively from left to right

• Atomic number increases are you go left to right in a row

Columns.

• Columns are called groups – elements all have the same number of electrons in their outer shell

• Atomic number increases as you go down a column

Properties are shared.

• Elements in a group have the same number of outer electrons therefore have similar chemical properties.

• These groups have names and are normally coloured differently on the periodic table.

Group 1.

• Alkali metals; all shiny and light metals• Doesn’t include Hydrogen• They are one electron away from being stable

(full shells).• A strong chemical desire to give away that 1

electron, means they are very reactive!

Group 2.

• Alkali Earth metals; all shiny light metals.• Reactive with water, oxygen and acid.• They are 2 electrons away from being stable.• Strongly basic• Tend to occur in nature as compounds.

Transition metals.

• Are in the middle • Often good conductor of electricity & heat.• Some are highly coloured and/or precious• E.g. copper, silver, goldThey are special because the can have more

than eight electrons in the outer shell one in from the outermost shell (variable valenacy).

Non metals.

• On the right hand side of the table.• Tend to be insulators (don’t conduct heat &

electricity).• Tend to be brittle.• Non metallic in colour, can be solids or gases

at room temperature.

Noble gases.

• Column 18.• All have full outer shells of electrons, so are

not reactive.• Often called inert gases.• Do not make ions.• All are gases at room temperature.

What do the atoms of an element look like?

• In order to draw an atom, you must know its atomic number & atomic mass.

3

Li

7

Atomic numberNumber of p & e

Atomic massNumber of p + n

Symbol

Working it out.

• Lithium has 3 protons and 3 electrons (atomic number).

• Lithium has 4 neutrons (mass-number).• As the first electron shell can only hold 2

electrons, it will have an arrangement of 2,1.

Lithium

Carbon

Drawing the first 20 elements.

• For each element, write the number of p & n into the nucleus (central circle).

• Then place the electrons in the shells, following the 2,8,8 rule.

• What patterns do you see?• The number of protons…• The number of electrons…

What about ions?

• When an atom loses or gains electrons, it either fills or empties its outer (valence) shell.

• It does this to become more stable.• When an atom gains electrons, it becomes

negatively charged (as it now has more electrons than protons).

• If it gains 1e it is X-, if it gains 2e it is X2-, if it gains 3e it is X3-

.

• These are called anions.

• If an atom loses electrons, it becomes positively charged (as it now has more protons than electrons).

• If it loses 1e it is Y+, if it loses 2e it is Y2+, if it loses 3e it is Y3+

.

• These are called cations.• Atoms with 4 electrons in the valence shell,

will not gain or lose electrons, they will share with another atom.

Predicting ions.

• If the atom has 1,2 or 3 electrons in the outer shell, it will lose them.

• If the atom has 5,6 or 7 electrons in the outer shell, it will gain them.

• If the atom has 4 electrons in the outer shell, it will not form an ion.

Naming ions.

• When an atom becomes an ion, it sometimes changes its name (like getting married)!

• If the ion is alone, it changes to become an -ide.

• Sulphide S2-, Oxide O2-

, Iodide I-.

• If the ion bonds with oxygen, it changes its name to an –ate.

• Sulphate SO42-, Nitrate NO3

2-.

• If ions bond together in a polyatomic ion, they also change their name.

• Hydroxide OH-, Ammonium NH4+.

• Oxygen ate an atom, but I’de rather be alone.

Chloride

Ions love to bond!

• Opposites attract in ionic chemistry.• Li+ wants to bond with a negative ion.• When Li+ bonds with Cl- they form LiCl; an

ionic compound.• The rule with ionic bonding is;When you see ions, you must STOP,

SWAP& DROP!

The rules.

• Same charge; combine symbols to make the compound formula.

• H+ + Cl- HCl• Mg2+ + O2- MgO

ClH

• Different charges; swap and drop the numbers and lose the charge.

• H+ + O2- H20• Fe3+ + S2- Fe2S3

• This is so you have an equal number of negative and positive charges.

OH H

• Different charges with polyatomic ions; use brackets when there is more than 1 polyatomic ion.

• Pb2+ + PO43+ Pb3(PO4)2

• Al3+ + NO3- Al(NO3)3

You must keep polyatomic ions together with brackets.

Complete…

The table of ions.

Mystery ions…

• Scientists have discovered two mystery ions X & Y.

• They are found in the first 20 elements.• When combined with OH- ions it becomes

X(OH)3.• What is ion X?• Ion Y combines with Li+

to become Li2Y.• What is ion Y?

Isotopes.

• An atom of an element, with more or less neutrons than usual.

• Doesn’t effect the charge of the atom, only its mass.• Protons & neutrons have a mass of 1, electrons have

so little mass, they don’t contribute.

C12 and C14 are isotopes of carbon.

C12 - 6p, 6n, 6eC14

- 6p, 8n, 6e

Identifying isotopes.

• Atoms can be identified using a mass spectrometer; this machine detects the mass of an atom.

• Could it tell the difference between; C12 and C14 ?

• Could it tell the difference between; N14 and C14 ?

Drawing isotopes.

• Draw 3 of the isotopes of Cl;Cl 17

35

Cl 1736

Cl 1737

17p18n

17p19n

17p20n

Isotope questions.

What changes between each isotope?Why does the atomic number stay the same?What does this tell us about the mass of an atom?Do they all form the same ion? Why or why not?How could you test to see which isotope you have?

Review atoms & ions sheet.

An electron is the smallest part of an atom (it has a negative charge). They are found in shells orbiting a central nucleus . The nucleus contains the protons (which have a positive charge) and the neutrons (which have no charge). The mass of the atom is determined by adding the number of protons and neutrons together, since they each have a mass of one .Normal atoms have the same number of electrons and protons making them neutral (no charge). Electrons are arranged in shells around the central nucleus in a special way; the first shell can hold two electrons, the second can hold eight electrons and the third can hold eight . We call this the 2,8,8 rule.

All atoms with the same number of protons are atoms of the same element. However some atoms of an element, have a different number of neutrons. These are called isotopes of the atom. This is why many of the element mass numbers have a decimal point.An atom which has lost or gained electrons is called an ion. Atoms lose or gain electrons from their outer or valence shell. Atoms which gain electrons become a negative ion, while those which lose become a positive ion. These ions are attracted to each other and form ionic bonds.

• Review atoms, ions & isotopes.• Making gas part 1.

Making hydrogen.

• Mg + HCl MgCl2 + H2

• Magnesium + hydrochloric acid Magnesium chloride + hydrogen gas.

• Hydrogen is a very light gas, we test for it using the pop test.

H H

Making oxygen

• KMnO4 KMn + 2O2

• Potassium permanganate + heat potassium magnate + oxygen gas.

• We test for oxygen using the glowing splint test.

O O

Making carbon dioxide.

• CaCO3 + HCl CaCl2 + CO2 + H2O

• Calcium carbonate + hydrochloric acid calcium chloride + carbon dioxide + water

• We test of carbon dioxide using the burning splint test.

CC O

What happens in a chemical reaction?

• In a chemical reaction, old bonds are broken and new ones are formed.

• The chemicals which go into a reaction are called the reactants.

• The new chemicals which are made in the reaction are called the products.

• Hydrochloric acid + Magnesium Magnesium Chloride + Hydrogen gas

• HCl + Mg MgCl2 + H2

• The bond between the H and the Cl was broken (taking in heat).

• The new bond between Mg and Cl was formed (giving out heat).

• The overall reaction was exothermic (heat producing).

• We use STOP, SWAP & DROP to work out what the formula of the products would be.

Step 1- breaking bonds

MgMg

MgMg

MgMg

MgMg

ClH ClH

Step 2- making bonds

HH

HH

HH

HH

HH

ClMgCl

Mg

ClCl

Balancing a chemical reaction.

• As you can see from the example above, there are different numbers of atoms on each side of the reaction (shown by the arrow).

• This means the reaction is unbalanced.• To balance the reaction;• Count up the number of atoms on each side of the

arrow (do this for each element).HCl + Mg MgCl2 + H2

1xH, 1xCl, 1xMg 1x Mg, 2xCl, 2xH

• Add more of the molecule you need, to the side of the equation which has less.

HCl + Mg MgCl2 + H2

HCl• Count up the number of atoms on each side

the arrow, if they are the same, add the big numbers by adding how many of each molecule you now have.

2HCl + Mg MgCl2 + H2

2xH, 2xCl, 1xMg 1x Mg, 2xCl, 2xH

• The equation is now balanced.• You may need to add molecules to each side

of the arrow in order to make them balance.• Keep adding and checking until you have the

same number of each element on each side of the arrow.

1. Fe + H2S04 Fe2(SO4)3 + H2

2. C2H6 + O2 H2O + CO2

3. KOH + H3PO4 K3PO4 + H2O

4. SnO2 + H2 Sn + H2O

5. NH3 + O2 NO + H2O

6. KNO3 + H2CO3 K2CO3 + HNO3

7. B2Br6 + HNO3 B(NO3)3 + HBr

8. BF3 + Li2SO3 B2(SO3)3 + LiF

9. (NH4)3PO4 + Pb(NO3)4 Pb3(PO4)4 + NH4NO3

10. SeCl6 + O2 SeO2 + Cl2

11. SnO2 + H2 → Sn + H2O

Changing the rate of chemical reactions.

1. Change the temperature.2. Change the concentration.3. Change the surface area.4. Use a catalyst.

Collision theory.

• In order for a reaction to occur, the reactants must have a successful collision. That is, they must hit together hard enough to break old bonds and form new ones.

• With every successful collision, a reaction takes place. The more successful collisions, the faster the reaction occurs.

Change the temperature.

• Increasing the temperature, gives the reactants more kinetic (movement energy) so when they hit each other, it is faster and harder. This means more successful collisions per second and a faster rate of reaction.

• Decreasing the temperature, gives the reactants less kinetic (movement energy) so when they hit each other, it is slower and softer. This means less successful collisions per second and a slower rate of reaction.

Change the temperature.

Increase Decrease

Change the concentration.

• Increasing the concentration, means there are more active molecules of the reactant to react, meaning there are more collisions overall. This means more successful collisions per second and a faster rate of reaction.

• Decreasing the concentration, means there are less active molecules of the reactant to react, meaning there are less collisions overall. This means less successful collisions per second and a slower rate of reaction.

Change the concentration.

Increase Decrease

Active particles

Change the surface area.

• Increasing the surface area, means there are more available molecules of the reactant to react, meaning there are more collisions overall. This means more successful collisions per second and a faster rate of reaction.

• Decreasing the surface area, means there are less available molecules of the reactant to react, meaning there are less collisions overall. This means more successful collisions per second and a slower rate of reaction.

Change the Surface area.

Increase Decrease

Use a catalyst.

• Adding a catalyst, lowers the amount of energy it takes for a collision to be successful. This means more collisions result in a reaction and a faster rate of reaction.

Experiment.

• Manipulate the temperature and concentration of HCl and the surface area of Mg.

• Graph your findings and compare to your notes.

Metal chemistry.

Metals v non-metals.Property Metal Non-metals

Colour Silver, except Au & Cu Many colours

Lustre Shiny Dull

Conducts heat Yes No

Conducts electricity Yes No (except graphite)

Malleable Yes No (brittle)

Ductile Yes No

Why do the metals share these properties?

Their atoms!

• Atoms of a metal form a lattice.• They are tightly packed, this gives density.• The layers slide, this makes them malleable and

ductile• Their delocalised (free) electrons, give them

thermal and electrical conductivity.• The free electrons, emit silvery-white light, this

gives lustre• The strong forces between atoms and the free

electrons, give strength and high melting points

e

Property Science

Solid at room temp

High melting point

Electrical conductor

Heat conductor

Dense

Ductile & malleable

Lustre & colour

Using metals.

• In order to choose the right metal for a particular application, you must know a few things about it.

• You must know;• How reactive it is.• How strong it is.• How expensive it is!

The Reactivity Series

The Reactivity Series lists metals (& carbon) in order of reactivity:

Potassium

Sodium

Calcium

Magnesium

Aluminium

Carbon

Zinc

Iron

Lead

Copper

Silver

Gold

Link the reaction of metals to their uses.

• Read the table to summarize the uses of metals.

• You must link the properties and reactivity to the use.

• State what you wouldn’t use the metal for an why.

• Pb; sinkers.• Fe; roofing.• Al; cooking foil.• Au; rings.• Hg; thermometers.• Zn; galavanize.• Sn; cans.• Ag; jewellery.• Cu; wires.

Gold

• I would use gold to make a wedding ring because it is inert. It will not react with acid, water or oxygen meaning you could wear it without it reacting.

• I wouldn’t use gold to wire my house, as it is too expensive.

Metal reactions.

• Do the MASH.• My car has a MOMO steering wheel.• Evil scientists say MoWaMoHaHa.

MASH

• Metal + Acid metal salt + hydrogen gas.

• The type of salt depends on the type of acid.• HCl (hydrochloric acid) gives chlorides.• H2SO4 (sulphuric acid) gives sulphates.

• HNO3 (nitric acid) gives nitrates.

Experiment.

• Carry out some reactions of metals and acids, record your observations and write an equation (word and symbol) for each reaction.

• Rule 1; MASH

Equations.

MoWoMaHaHa

• Metal + water metal hydroxide + hydrogen gas

• The type of hydroxide depends on the type of metal.

Experiment.

• Carry out some reactions of metals and water, record your observations and write an equation (word and symbol) for each reaction.

• Rule 2; MoWoMaHaHa

Equations.

MOMO

• Metal + Oxygen metal oxide.

• This can happen fast use fire!• This can be slow rusting.

Experiment.

• Carry out some reactions of metals and oxygen, record your observations and write an equation (word and symbol) for each reaction.

• Rule 3; MOMO

Slow MOMO.

Rusting.• Rusting is the name given when Iron and oxygen react.

• About 21% of air is oxygen and small amounts are found in water. Water is required for rusting to take place. There are several ways of dealing with rust:

1) Regular painting or oiling

2) Galvanising – this is when iron objects are coated with zinc, this react with oxygen making an unreactive layer

3) Making objects out of a non-rusting metal, such as stainless steel

4) Attaching zinc bars to ships – the water will react with the zinc before it reacts with the iron, because zinc is more reactive

The rusting of iron and steel is a costly problem and can be expensive to prevent. If it is not prevented, the rusted iron and steel may need to be replaced.Think about all the things that we use iron and steel for!

Rusting experiment.

A B C D E A- water, no top

B- silica gel + top

C- Boiled water + top

D- water, no top, copper wire

E- water, no top, zinc wire

More metal reactions.

• There are 3 more metal reactions which you need to know about;

• Metal carbonate + Acid metal salt + carbon dioxide + water

• Metal hydrogen carbonate + Acid metal salt + carbon dioxide + water

• Metal hydroxide + Acid salt + hydrogen

Metal carbonates & hydrogen carbonates

Metal carbonate Observation Salt made

Copper II carbonate

Magnesium carbonate

Potassium hydrogen carbonate

Equations

Last one, promise!

• Neutralisation.• Acid + Base Salt + Water

• Ahhhhhhh heartburn!

Which antacid is best?

• Complete the “Ahhhhh heartburn” experiment.

• You are to write this experiment up using the standard sheet please

Rāhinā 24th Mahuru.

• Finish mind map.• Collect revision sheet.• Complete revision sheet.• Test on Wednesday Pass

test