P5.1 - The Nucleus

Question 1

What is in the nucleus? [2]

Answer 1

• protons
• neutrons

Question 2

Why is the nucelus significant? [1]

Answer 2

most of the mass of an atom is concentrated here

Question 3

What are protons? [3]

Answer 3

• positively charged particles
• relative charge of +1
• relative mass of 1

Question 4

What are neutrons? [3]

Answer 4

• neutral particles
• no charge (0)
• relative mass of 1

Question 5

How do you find out the atomic number of an atom? [1]

Answer 5

the number of protons

Question 6

How do you find out the atomic mass of an atom? [1]

Answer 6

the total number of protons and neutrons

Question 7

What are electrons? [3]

Answer 7

• spin around the nucleus in the outermost shell
• relative charge of -1
• relative mass of 1/2000

Question 8

What is a nucleon number? [1]

Answer 8

the mass number or the atomic mass

Question 9

What is the nuclide notation? [1]

Answer 9

ᴬ
X
ᶻ

Question 10

What do the letters in nuclide notation represent? [3]

Answer 10

• A = mass number
• Z = atomic number
• X = element

Question 11

What is an isotope? [2]

Answer 11

atoms of the same element with the same number of protons but different numbers of neutrons

Question 12

What do isotopes have in common and different? [2]

Answer 12

• common: same chemical properties
• different: physical properties

Question 13

What does it mean if an isotope is radioactive? [2]

Answer 13

• their nuclei are unstable and break down over time
• this emits radiation in the form of alpha particles, beta particles or gamma rays

Question 14

What is an example of different isotopes? [2]

Answer 14

• Carbon-12 = stable, 6p and 6n
• Carbon-14 = radioactive, 6p and 8n

Question 15

What is the relationship between the proton number and the relative charge on a nucleus? [2]

Answer 15

• realtive charge of a nucleus is determined by the number of protons as neutrons don’t contribute to the charge
• neutrons only contribute to the mass of the nucleus

Question 16

What is an example of the relationship between the proton number and the relative charge on a nucleus? [1]

Answer 16

e.g. Helium atom has 2 protons = relative charge of its nucleus is +2

Question 17

What is nuclear fission? [2]

Answer 17

the process where a large, unstable nucleus splits into two smaller nuclei, releasing energy

Question 18

How does nuclear fission work? [3]

Answer 18

• a tiny particle called a neutron hits a big atom, a large nucleus
• the large nucleus breaks into two smaller pieces and releases a lot of energy
• more tiny neutrons fly out and can hit other atoms making a chain reaction

Question 19

What is nuclear fusion? [2]

Answer 19

the process where two small nuclei join together to form a large nucleus, releasing energy

Question 20

How does nuclear fusion work? [3]

Answer 20

• occurs in extremely hot temperatures and pressures like the sun
• nuclei smash together really hard and stick together to make a bigger atom
• the resulting nucleus is larger and gives of a lot of energy

Question 21

What is radiation? [2]

Answer 21

• the transfer of energy in the form of electromagnetic waves or particles
• without the need of a medium to travel through