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Metals and Non-metals: Properties, Reactivity, and Chemical Families, Study Guides, Projects, Research of Organic Chemistry

This shows that chlorine is more reactive than bromine. A similar reaction occurs if chlorine is added to a solution of potassium iodide, with brown iodine ...

Typology: Study Guides, Projects, Research

2021/2022

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Metals and Non-metals
Metallic elements occupy the
left side and middle of the
periodic table.
Non-metals are found on the
right side of the periodic table.
Testing for metals and non-metals:
metals conduct electricity; non metals do not conduct electricity – except graphite !
•oxides of metals form alkaline solutions in water
•oxides of non-metals form acidic solutions in water
Experiments to show that magnesium is a metal:
electrical conductivity test: conducts electricity
burning to form magnesium oxide, dissolving
magnesium oxide in water, and testing pH: alkaline
solution
2Mg(s) + O2(g) 2MgO(s)
Experiments to show that sulphur is a non-metal:
electrical conductivity test: does not conduct
burning to form sulphur dioxide, dissolving sulphur
dioxide in water, and testing pH: acidic solution
S(s) + O2(g) SO2(g)
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Metals and Non-metalsMetallic

elements occupy the

left side and middle

of the

periodic table. Non-metals

are found on the

right

side of the periodic table. Testing for metals and non-metals: • metals conduct electricity; non metals do not conduct electricity – except graphite !• oxides of

metals

form

alkaline

solutions in water

  • oxides of

non-metals

form

acidic

solutions in water

Experiments to show that magnesium is a metal:• electrical conductivity test:

conducts electricity

  • burning to form magnesium oxide, dissolvingmagnesium oxide in water, and testing pH:

alkaline

solution

2Mg

(s)^

+ O

2(g)

2MgO

(s)

Experiments to show that sulphur is a non-metal:• electrical conductivity test:

does not conduct

  • burning to form sulphur dioxide, dissolving sulphurdioxide in water, and testing pH:

acidic solution

S^ (s)

+ O

2(g)

SO

2(g)

Chemical Families Elements in the same Group have the same number of outer shell electrons. The

same

number of outer shell electrons

means

similar chemical properties

  • so each Group is a

chemical family.

Group 1 – The Alkali Metals

Group 7 – The Halogens

Group 0 – The Noble Gases

Comparing Group 1 metals to typical metals

Trends Going down Group 1 the metals

  • become

softer

  • get

more dense

-^ melt

and

boil

at

lower

temperatures

Chemical Properties of alkali metals Group 1 metals are very reactive! They are normally stored under oil. The oil acts as abarrier preventing them from reacting with oxygen in the air, or with water.

An alkali metalin water

An alkali metalstored in oil

Trend Reactivity

increases

as

we go

down

the group

Explaining the order of reactivity in Group 1 Group 1 elements react by losing their outer shell electron to form metal ions with a 1+charge, and hence gain a full outer shell.The further away from the positively charged nucleus the outer shell electron is, the easier itis for the atom to lose it, so the more reactive the element is.This is because the attraction between the negatively charged electron and the nucleus getsweaker the further away the electron is, and the more shells there are in between.

Group 7 - The Halogens The Halogens are the elements in Group 7They are

non-metals,

having

coloured vapours

The halogen elements consist of molecules made up of

pairs

of atoms. e.g. chlorine is Cl

2(g)

They each have 7 electrons in their outer shell

Trends in the physical propertiesof the halogens As we go down Group 7:

•^

colour increases in intensity

-^

state goes from gas to liquid to solid

-^

melting point increases

-^

boiling point increases

We would therefore predict that

astatine

would be a very dark (black) element, solidat room temperature, and with a meltingand boiling point higher than those of iodine.

Trend in reactivity

Reactivity of the halogens

decreases

as we go

down

the group (opposite trend to Group 1)

Chemical Properties The halogens have 7 electrons in their outer shell. They react by gaining an electron tocomplete their outer shell, or by sharing electrons with other atoms.Reactions with metalsWhen a halogen atom

gains an electron

it forms an

ion with

a 1- charge

, which we call a halide ion: fluoride

- F

chloride

Cl

bromide Br

iodide

- I

(see notes on reactions of Group 1metals with halogens)

Reactions with non-metalsHalogens can react with other non-metals, sharing their outer shell electrons to formbonds.

e.g.

H2(g)

+^

Cl

2(g)

2HCl

(g)

hydrogen + chlorine

hydrogen chloride

Group 8 or 0 - The Noble Gases The noble gases are in Group 8 (aka Group 0)They are all

colourless gases

They are very

unreactive

They exist as

individual atoms

rather than forming molecules.

Uses - balloons:Helium

is used (rather than hydrogen) in lighter-than-air

balloons because its lack of reactivity means it will notignite. The only other gas with a sufficiently low density ishydrogen, which is extremely flammable and dangerous. Uses – in discharge tubes: When electricity is passed through a glass tube containing anoble gas at low pressure, the atoms are excited and light isproduced. Each noble gas produces a different colour. Neon

is the brightest, hence its use in advertising signs.

Uses – inert atmospheres:Argon

is used to fill light bulbs because it

is very unreactive. It prevents thetungsten filament from reacting withoxygen when it gets hot, and “burningout”. It is also used when welding toprevent oxygen getting to the hot metaland causing corrosion.

Explaining the lack of reactivity Their lack of reactivity is because they have a

full outer shell

and

therefore

don’t form stable ions

It takes a lot of energy to rearrange the full outer shell so as to beable to form bonds with other elements to form a molecule, sothis doesn’t happen either.

Ar