Atoms and isotopes test

Question 1

What is the radius of an atom?

Answer 1

1 x 10^-10 metres

Question 2

What charge does a nucleus have?

Answer 2

positive charge from the protons

Question 3

How does the electron arrangement change with the absorption of the electromagnetic radiation?

Answer 3

• moves further from the nucleus
• higher energy level

Question 4

How does the electron arrangement change with the emission of electromagnetic radiation?

Answer 4

• moves closer to the nucleus
• lower energy level

Question 5

What is the number of protons in an element called?

Answer 5

Atomic number

Question 6

What is the number of protons and neutrons in an element called?

Answer 6

mass number

Question 7

Does an atom have an overall charge?

Answer 7

NO

Question 8

What do you call atoms of the same element that have a different number of neutrons?

Answer 8

isotopes

Question 9

What did John Dalton propose?

Answer 9

atoms are tiny invisible spheres
early 1800’s

Question 10

What did J.J. Thompson discover?

Answer 10

• atoms contain negative charge, he discovered the electron
• plum pudding model
• ball of positive charge with electrons embedded in it

1897

Question 11

How did Rutherford’s alpha particle experiment go?

Answer 11

• fired alpha particles at a piece of thin gold leaf
• alpha particles have 2 protons & 2 neutrons (positively charged)

Question 12

What would happen in the alpha particle experiment if the plum pudding model was correct?

Answer 12

all of the alpha particles would go straight through or almost straight through the soft pudding

Question 13

What did Rutherford find instead?

Answer 13

• most alpha particles went through
• some deflected by large angles and a few bounced back

Question 14

Describe Rutherford’s new model based on the results of his experiment

Answer 14

• nuclear model
• most mass in concentrated in small nucleus at the centre
• electrons orbit nucleus

Question 15

What caused some alpha particles to be deflected by large angles?

Answer 15

• they passed by very closely near the nucleus

Question 16

Why did only a few of the alpha particles to bounce back?

Answer 16

• nucleus is relatively small
• therefore very unlikely to directly hit it

Question 17

What did Niels Bohr discover?

Answer 17

• electrons orbit the nucleus at specific distances called energy levels/ shells
• theoretical calculations agreed with experimental data

1913

Question 18

What did Rutherford discover?

after his alpha particle experiment

Answer 18

• protons
• the overall positive charge of nucleus can be divided into smaller positive particles
• each one called a proton

1917

Question 19

What did James Chadwick discover?

Answer 19

• neutrons