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Flashcards in JJO History of the Atom and Periodic Table Deck (21)
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1

What charge does an electron have?

-1, negative

2

What charge does a proton have?

+1, positive

3

What charge does a neutron have?

Neutral, no charge

4

Which subatomic particles are found in the nucleus?

Protons and neutrons

5

What charge does the nucleus of an atom have? Explain why.

Positive

Because it contains protons which are positively charged and neutrons which have no charge.

6

Where is most of the mass of the atom found? Explain your answer.

In the nucleus

  • Because the nucleus contains protons and neutrons which both have a mass.
  • Electrons which have no mass are the only particles outside the nucleus.

7

What is most of an atom made of?

Empty space

8

How big is the nucleus of an atom compared to a whole atom.

The radius of the nucleus is 10,000 times smaller than the radius of the atom (1/10,000)

9

How were elements organisined in early versions of the perodic table.

In order of atomic mass

10

What was the main problem with early versions of the periodic table.

  • Some elements were grouped with elements with very different properties.
  • For example, iron was in a group with oxygen.

11

  1. How did Mendeleev organise the elements in his periodic table?
  2. What unusual thing did he need to do to make this possible?

  1. He grouped elements with wimilar properties.
  2. e had to leave gaps to make this possible.

12

Why did the discovery of Gallium support Mendeleevs ideas. 

Clue: Gallium is in the same group as aluminium.

  1. Gallium fitted in one of the gaps that Mendeleev had left.
  2. And it had similar properties to aluminium which was in the same group.

13

Put these things in order based on when they were discovered (electrons were discovered first):

Electrons

Protons

The nucleus

Neutrons

Electron shells

 

 

Electrons

The nucleus

Electron shells

Protons

Neutrons

14

Which did Dalton think the atom was like?

An indestructible sphere: It couldn't be broken into smaller particles.

15

What did Thomson think the atom was like?

A sphere of positive charge

With scattered electrons

Like a plum pudding

16

Who discovered the nucleus?

Rutherford

17

Who discovered electron shells?

Bohr

18

How is Bohrs model different to the current model of the atom?

Bohr though the nucleus was a dense positively charged area (which we still believe now) but he did not realise that it contained positive and neutral particles.

19

What is the charge of an atom? Explain your answer

Neutral

Because atoms contain equal numbers of positively charge protons and negatively charged electrons.

20

If an atom loses or gains electrons, what will it become?

An ion

21