simmyhall's version from 2015-05-29 21:54

Section 1

Question Answer
Dobereiner Arranged elements in groups of 3- didn't work for all element s
Newlands Arranged in octaves (similar prop)-arranged in relative atomic mass / didn't work for all and caused problems when new elements discovered
Mendeleev Put in order of relative atomic mass and left gaps and predicted their properties -successful
Mass number(top)Protons and neutrons
Atomic number bottomProtons and electron number too
Across Period- how many shells
DownGroup- number of electrons in outer shell

Section 2

Question Answer
Group one reactivity As you go down more reactive
Group one melting and boiling points Go down as you go down
Properties of group one Soft ,low density ,shiny surface when cut but reacts with Air -layer in metal oxide
Precautions Use small amount of dilute concentration ,safety glasses ,avoid working near naked flame

Section 3

Question Answer
Group 7 reactivity Goes down as you go down
Melting point and bp Goes up as you go down
Density Increase as you go down
Trend in statesGas liquid solid
At room temp become Darker as you go down

Section 4

Question Answer
Protons Relative mass 1 Relative charge +1
Neutrons Relative mass 1 relative charge 0
Electron Relative mass negligible relative charge -1
Looses electron Positively charged
Gains electronNegatively charged
Ionic Metal and non metal
Sodium chloride Giant crystal lattice - electrostatically attracted
Sc conducts When molten or dissolved -strong forces weakened ions free to move

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