Periodic Table, Bibliography
Book: Resemarie Gallagher, Paul Ingram.…
- Group 7 is a group of non-metals elements.
- Form coloured gases.
- Are poissonous.
- For diatonic molecules, "Cl2."
Trends in their chemical properties
- they are the most reactive elements
- "F", "Cl", "Br", "l" react in a similar way.
reactivity decreases as you go down
Trends in their physical properties
- The group of nalgens is the only table group wich contains elements in all three faliliar states of matter at standard temperature and pressure.
- The hydrogen elements, are extrely toxic.
- Poor conductor of heat and electricity.
(F) is a pale yellow gas
(Br) dark red liquid
(l) lack solid and when heated it forms a purple vapour.
Why are they so reactive?
Because it has a strong drive to react to others elements or compounds, to gain this electrons.
- Ionic compounds.
- Non-metals atoms.
- Shares electrons, formings molecules with covalent bonds
Why does reactivity decrease down Group VII?
- Halogens atoms react to gain or share an electron.
- The more shells there are, the further the outer shell is from nucleus.
How the halogens react with halides?
1) when chlorine water is added to a colourless solution of potassiuum bromide, its reaction is that bromine is pushed out of its compound or displaced.
2) when chlorine water is added to a courless solution of potassium iodide, solution turns into red and iodine has been displaced.
But what happens if you use bromine or iodine instead of chlorine?
- A halogen will displace a less reactive halogen from a solution of its halide.
Across the periodic table
Trends across period 3
There are thrends within groups, and also trends across a period.
- The number of valency electrons increases by 1 each time.
- The elements go from metals to non-metals,
- The oxides of the metals are basic.
- Non-metals are acids
- METALLOID :
The change from metal to non-metal
- Not clear-cut
- Silicon is a metalloid
- Metals conducts electricity
Is the number of electrons its atoms lose, gain or share to form a compound.
- The valency does match the number of vanlency electrons, up to Group IV.
- The valency matches the charge on the ion, where an element forms ions.
What about reactivity?
Metals atoms lose their auter electrons when they react, while non-metal atoms accept or share electrons.
- Reactivity decreases across the metals.
- Reactivity increases across the non-metals.
Overview of the periodic table
- The periodic table is a way of classifying elements in order, it shows them in order of their proton number.
- Metals and non-metals are separated.
- Elements separated by groups
- Group 0 --> Noble gases
- Group 1--> alkali metals.
- Group 2 -->alkaline earth metals
- Group 3--> halogens
- Group 4 --> Crystallogens
- Group 5--> pnictogens
- Group 6 --> Chalcogens
- Group 7 --> Halogens
- The outer-shell electrons are also called valency electrons.
- All elements in a group haves similar reactions.
- Group 0 are unreactive
- The period number tell us the number of electrons shells in the atoms.
- 80% of the elements are metals, metals and non-metals have different properties.
- Hydrogen its alone at the periodic table because, it has no auter electron, forms a positive ion, and it is a gas, but usually react like a non-metal.
- The transition elements are all metals.
- Some of the elements are created in a lab, (they are artificial), they are radioactive, and their atoms break down very quicky.
- If you know where did the elements, you can use the patterns and trends to predict how it will behave.
The alkali metals
- Are in the group 1.
- Violently reactive, except the first 3.
Their physical properties
- They are not typical metals because, they softer than most others.
- Are ligther, " low density."
- Float on water.
- Have low melting an boling point.
The trends in their phisical properties
- It has an overall increase and decrease for each propertie, as you go down the table,"trend".
1) Reaction with water
react violantly with water.
- The alkali metals react vigorously with water, hydrogens bublles off, leaving solutions of their hydroxides.
2) Reaction with chlorine
- If you heat does three metals are going to plunge them into gas jars of chlorine, they burst into flame.
3) Reaction with oxygen
- Also burst into flame.
- They burn fiercely to form oxides.
- Dissolves into water to form alkaline solutions.
- Reactivity increase as you go down.
Why do they react in a similar way?
- All alkali metals react in a similar way because, they have the same number of valency.
Why are they so reactive?
- This is because, they need to lose only one electron, to gain a stable outer shell.
- They become ions.
- The compounds they forms are ionic: Na+ and Cl-.
- Compounds are white solids.
The noble gases
- GROUP 0
- Courless gases
Trends in their physical properties
- Gases are more denser because of the mass in the atoms increases.
- Is more dificult to separate them to form gases.
- The atoms increase in size and mass.
- The density of the gases increases.
- The boiling point increases.
Uses of the noble gases
Glow when a current is passed through them at low pressure.
- Hilium to fill baloons
- Argon to provide and inert atmosphere. ex: To protect elements that are being welded.
- Neon is used in adversing signs. ex: Stop signal
- Krypton is used in lasers. *ex: eye surgery
- Xenon gives a light. ex: lighthouse lamps
The Transition elements
- The block of 30 elements at the middle of the periodic table
- All the metals
- Hard, tough and strong
- High melting points.
- Good conductors of heat and electrecity.
- High density
Their chemical properties
- They are much less reactive than the group I metals.
- They show no clear trend in reactivity, unlike the Group I metals.
- Most transition elements form coloured compaunds.
- Most can Form ions with different charges.
- They can form more than one compounds with another elements.
- Most transition elements can form complex ions.
- Strong transition elements are for structures, (bridges, buildings, cars.)
- Iron--> steels
- Making alloys. ex: stainless steel.
- Conductors of heat and electricity. ex: copper is used for electric wiring.
- Acts as catalysts ex: iron used as a catalyst in making ammonia.