C2

Question 1

John Dalton

Answer 1

1808- he created a table of 20 elements, but many of them were compounds, that were arranged in order of weight. He used his own symbols.

Question 2

John Newlands

Answer 2

1864- Aranged elements in rows of 8, in order of increasing mass with well known symbols. It didn’t work because he hadn’t left gaps for new elements.

Question 3

Dmitri Mendeleev

Answer 3

1869- ordered elements on their mass and their properties. He had to try several ways until he found one he thought worked, and left gaps for new elements which ,when discovered, fit in the right places.

Question 4

What determines an elements position in the periodic table?

Answer 4

The atomic number, as the number of electrons in the outermost shell determine reactivity.

Question 5

(Group 1) the alkali metals

Answer 5

Have 1 electron on outer shell, are more reactive lower in the group, softer than most metals, react with oxygen.

Question 6

(Group 7)The halogens

Answer 6

Down the group they get less reactive and have higher melting/boiling points. All missing one electron from outer shell.

Question 7

Atom size within groups

Answer 7

As you go down a group, the number of shells occupied by electrons increases, meaning atoms are larger lower down in a group

Question 8

Effects of large atoms on reactivity

Answer 8

Larger atoms lose electrons more easily and gain them less easily (Less reactive) because inner electrons shield.