the periodic table

how were elements organised in the early 1800s

by atomic weight and physical and chemical properties

What did Mendeleev do to the periodic table

left gaps in the periodic table for undiscovered elements

How is the modern periodic table arranged

by atomic number

who do metals form

positive ions because they lose electrons to form a full outer shell

what do non-metals form

they do not form positive ions because they gain electrons to form a full outer shell

Why do metals get more reactive as you go down the group

outershell electrons gets futher away from nucleus

because atoms get bigger and has more shells

This decreases the attaction of the other shell electrons to the nucleus making them more reactive

why do metals reactivity increase as you go down the group

easier for elements to react and lose electrons

propeties of metals

malleable

strong

good conducters of heat and electrricity

properties of non metals

poor conducters of electricity

lower density

what is group 0 known for

noble gases

Why do group 0 not react with other metals

outershell if full making them stable and unreactive

Are group 0 molecules?

no they are single monatomic atoms

what happens to the boiling points as you go down group 0

boiling point increases as you go down the group

why does boiling point increases as you go down the group in noble gases

due to increasing number of electron which increase intermolecular forces

what are group 1 elements called

alkali metals

are alkali metals highly reactive

yes however they are soft metals low density

does the reactivity increase or decrease when you go down group 1 metals

reactivity increases because outer electron is easily lost due to increasing distance from the nucleus and a weaker attraction

what do alkali metals form

ionic compounds with non metals

what are the melting points and boiling points in group 1 metals

low melting and boiling points and a higher relative atomic mass

what are halogens called

halogens and they are non metals

what happenes as you go down the group in halogens

boiling/ melting point increases (intermolecular forces get stronger)

colour gets darker

reactivity decreases

why is it difficult for group 7 to gain electrons

number of shell increases and atom gets bigger

meaning that there is less attraction between nucleus as electron