3.1 The Peridoic Table Flashcards
What did the periodic table used to be ordered by?
Arranged by properties
Who first organised the periodic table in regular pattern
Newlands
How did Newlands organise the periodic table?
In order of mass with similar properties
What was Newlands theory of the Periodic table called?
The law of octaves
Who was the scientist that next organised the periodic table and paved the way for the modern table?
Mendeleev
What did Mendeleev order the periodic table in?
By atomic mass
Physical and chemical properties
What did Mendeleev do that was profound?
He left gaps in the table for undiscovered elements and predicted their properties
What helped shape the modern periodic table?
The discovery of protons and electrons enabled elements to now be arranged in proton number
What is a group?
A vertical column
What is a period?
A horizontal column
What does another period signify in terms of subatomic particles?
As the period goes down another electron shell is added
What are group 1 elements called?
The alkali metals
Name some properties of alkali metals?
1 electron in the outer shell
Not very dense - floats on water
Very reactive with group 7 to produce salts
Conducts electricity
Reacts aggressively with water to produce an alkali solution
Produces a white compound
Low melting and boiling points
What is the reactivity in group 1?
More reactive as it goes down
Why does the reactivity of group 1 increase as it goes down?
The outer electron is further away from the nucleus
This is because there are more shells
So the attraction between the outer electron and the nucleus is weaker
Therefore the electron can be lost more easily making the element more reactive
What gas is produced when group 1 elements react with water?
Hydrogen
What happens when a more reactive group 1 reacts with water?
It reacts faster
Lilac sparks/flame is produced
Name properties of the transition elements?
Conducts electricity Malleable and ductile Reacts less vigorously with water Strong metallic bonds High melting and boiling points Stronger than group 1 Often coloured compounds Used as catalyst
What is group 7 called?
The halogens
What are some properties of the Halogens?
Reacts with metal to form ionic compounds
Reacts with non-metals to form covalent bonds (molecules)
Low melting and boiling points
7 electrons in the outer shell
What states are some halogens at room temperature?
Florine - Pale yellow gas
Chlorine - Green gas
Bromine - Red/brown liquid
Iodine - Grey solid
What is the reactivity of group 7?
Reactivity increases as it goes up
Why does the reactivity in group 7 increase upwards?
The attraction to the outer shell and the nucleus is stronger with less shells
This pulls electrons in quicker making it more reactive
What happens in a reaction with two halogens?
A more reactive halogen can displace a less reactive halogen from a compound
