JJO History of the Atom and Periodic Table Flashcards
What charge does an electron have?
-1, negative
What charge does a proton have?
+1, positive
What charge does a neutron have?
Neutral, no charge
Which subatomic particles are found in the nucleus?
Protons and neutrons
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.
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.
What is most of an atom made of?
Empty space
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)
How were elements organisined in early versions of the perodic table.
In order of atomic mass
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.
- How did Mendeleev organise the elements in his periodic table?
- What unusual thing did he need to do to make this possible?
- He grouped elements with wimilar properties.
- e had to leave gaps to make this possible.
Why did the discovery of Gallium support Mendeleevs ideas.
Clue: Gallium is in the same group as aluminium.
- Gallium fitted in one of the gaps that Mendeleev had left.
- And it had similar properties to aluminium which was in the same group.
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
Which did Dalton think the atom was like?
An indestructible sphere: It couldn’t be broken into smaller particles.
What did Thomson think the atom was like?
A sphere of positive charge
With scattered electrons
Like a plum pudding
