Atomic Structure+ Isotopes

Question 1

What is the mass of an electron?

Answer 1

Almost 0

Question 2

What is the charge of an electron?

Answer 2

-1

Question 3

What is the mass of a proton?

Answer 3

1

Question 4

What is the charge of a proton?

Answer 4

+1

Question 5

What is the mass of a neutron?

Answer 5

1

Question 6

What is the charge of a neutron?

Answer 6

0 (neutral)

Question 7

What is the mass number in an element?

Answer 7

Number of protons+ neutrons

Question 8

What is the atomic number of an element?

Answer 8

Number of protons

Question 9

What is an isotope?

Answer 9

An atom with the same number of protons but different number of neutrons

Question 10

How have the ideas of atoms changed over time?

Answer 10

• originally spheres that could not be divided into anything smaller
• now known to have a nucleus (made up of protons and neutrons) surrounded by electrons that orbit in their energy levels.

Question 11

What are the three subatomic particles that make up an atom?

Answer 11

Proton+ electron+ neutron

Question 12

Compare the difference in size of protons, neutrons and electrons.

Answer 12

• protons and neutrons= same size
• electrons are much smaller

Question 13

What is the size of an atom?

Answer 13

1 times 10 to the power of -10 in diameter

Question 14

Compare the size of a nucleus to the size of an atom

Answer 14

Diameter of nucleus about 10 thousand times smaller than atom

Question 15

Compare the size of an electron with a nucleus

Answer 15

Diameter at least 1 thousand times smaller than that of nucleus

Question 16

What is the overall charge of atoms of an element containing equal number of protons and electrons?

Answer 16

no overall charge

Question 17

True or false: protons, neutrons and electrons are evenly distributed in an atom?

Answer 17

False they are not evenly distributed in an atom

Question 18

Describe the structure of an atom.

Answer 18

• protons and neutrons exist in a dense core at the centre of the atom (nucleus)
• electrons spread out around edge of the atom and orbit the nucleus in shells

Question 19

Describe the structure of a sodium atom, include masses and charges of all particles. ( mass number=23 atomic number= 11)

Answer 19

• sodium has 11 POSITIVE PROTONS
• sodium has 11 NEGATIVE ELECTRONS
• sodium has 12 NEUTRONS
• PROTONS AND NEUTRONS both have a mass of 1 and are found in nucleus
• ELECTRONS have NO MASS and orbit in shells.
• arrangement in sodium is 2,8,1

Question 20

What happens to electrons if electromagnetic radiation is absorbed by the atom?

Answer 20

Move up energy levels

Question 21

What happens to the electrons if electromagnetic radiation is emitted by the atom?

Answer 21

Electrons move down energy levels

Question 22

Describe how a money detector works in 3 steps.

Answer 22

• banknotes contain strip of paper to show they are genuine
• when uv light (electromagnetic radiation) is absorbed, electrons become excited+ move to higher energy levels
• when they fall back down visible light (electromagnetic radiation) is emitted and the strip glows

Question 23

What is ionising radiation?

Answer 23

If enough energy is ABSORBED then electrons may be lost completely+ positive ions formed

Question 24

True or false: isotopes have the same proton number

Answer 24

true- if they didn’t they wouldn’t be the same element

Question 25

Who created the original thought of atoms being spheres that could not be divided into anything smaller?

Answer 25

John dalton

Question 26

Who found that electrons could be removed from atoms?

Answer 26

JJ Thomson

Question 27

Who created the plum pudding model?

Answer 27

JJ Thomson

Question 28

Describe the plum pudding model

Answer 28

Atoms were thought to have a cloud of positive charge with electrons dispersed throughout this cloud

Question 29

What experiment did enterst Rutherford and Ernest marsden carry out?

Answer 29

The alpha particle scattering experiment

Question 30

What subatomic particles did Rutherford discover?

Answer 30

Protons

Question 31

What did Bohr propose in the atomic structure?

Answer 31

That the electrons orbit the nucleus at specific distances

Question 32

What did James Chadwick discover?

Answer 32

Neutrons (in the nucleus)

Question 33

When was the first discovery of atoms?

Answer 33

1803

Question 34

When was the plum pudding model discovered?

Answer 34

1897

Question 35

Who and when was the nucleus model discovered?

Answer 35

1909 by Ernest Rutherford

Question 36

When was the Bohr model discovered?

Answer 36

1913

Question 37

When was the atomic structure we use now discovered and by who)

Answer 37

James Chadwick in 1932

Question 38

What are two similarities of the nuclear model and the plum pudding model?

Answer 38

- both contain positive charge - both have electrons

Question 39

What is the 4 difference of the plum pudding model and the nuclear model?

Answer 39

- positive charges spread out in plum model but only in NUCLEUS of nuclear model - electrons spread through atoms in plum model and only in shells of nuclear model - nuclear model has nucleus - nuclear model has protons and neutrons

Question 40

Describe the alpha particle scattering experiment in two steps

Answer 40

- Rutherford used radioactive source to fire positive charges alpha particles at thin gold foil - if atom was like plum pudding model all of particles would go straight through+ small amount of deflection

Question 41

What were the three observations from the scattering experiment?

Answer 41

- most alpha particles went straight through= atom is mostly empty space - some were bent off course= alpha particles hit positive charge (proton) - very small number came back= all positive charge concentrated in small space centre of the atom