chem final unit 2

Question 1

Democritus

Answer 1

Democritus proposed that matter is composed of small, indivisible particles called atoms

Question 2

dalton

Answer 2

(billiard ball) Introduced the idea of atomic mass: He showed that elements have different atomic weights.

Question 3

thomspson

Answer 3

(plum pudding)Thomson is best known for discovering the electron, Thomson conducted experiments using a cathode ray tube,

Question 4

cathode ray tube

Answer 4

To figure out the charge of an electron: If electrons had a + charge they would move towards the negative plate, etc.
Result: the beam of electrons moved towards the + plate, meaning they have a - charge

Question 5

rutherford

Answer 5

(nuclear model)conducted the gold foil expierment and concluded The atom has a dense, positively charged center. The fact that some alpha particles were deflected or bounced back meant they had hit something small and dense in the center of the atom. Rutherford concluded that this was the nucleus

Question 6

daltons atomic theroy

Answer 6

John Dalton’s atomic theory stated that all matter is made of indivisible atoms, and atoms of the same element are identical in mass and properties. Atoms combine in simple ratios to form compounds, and in chemical reactions, they are rearranged but not created or destroyed.

Question 7

proton

Answer 7

Relative Charge: +1
Relative Mass: 1

Question 8

neutron

Answer 8

Relative Charge: 0
Relative Mass: 1

Question 9

electron

Answer 9

Relative Charge: -1
mass: ~ 0

Question 10

isotope

Answer 10

An isotope is a version of an element that has the same number of protons (so it’s the same element), but a different number of neutrons. This means isotopes of an element have the same atomic number but different atomic masses.
Carbon-12 (¹²C) has 6 protons and 6 neutrons.
Carbon-14 (¹⁴C) has 6 protons and 8 neutrons.

Question 11

alpha radiation

Answer 11

4/2 He

Question 12

beta radiation

Answer 12

0/-1

Question 13

gamma radiation

Answer 13

0/0 &

Question 14

decay

Answer 14

whole > particle + rest of whole

Question 15

strong force

Answer 15

It is the force that holds the nucleus of an atom together, acting between protons and neutrons. acts over SMALL diferences

Question 16

electrostatic force

Answer 16

It is the force that causes like charges to repel and opposite charges to attract.

Question 17

fission

Answer 17

Fission is a nuclear reaction where a large, unstable atomic nucleus splits into two smaller nuclei, releasing a large amount of energy. an uncontrolled chain reaction emits the energy

Question 18

fusion

Answer 18

Fusion is a nuclear reaction where two light atomic nuclei combine to form a heavier nucleus, releasing a tremendous amount of energy.

Question 19

halflife

Answer 19

A half-life is the time it takes for half of the atoms in a sample of a radioactive substance to decay or transform into a different element. After one half-life, half of the original substance remains, and the other half has decayed.

Question 20

how to calculate half life

Answer 20

• Identify the half-life
• Calculate how many half-lives have passed, years/hl
• Use the chart to track the amount of substance after each half-life.

Question 21

nuclear reactor

Answer 21

A nuclear reactor is a device used to initiate and control a sustained nuclear chain reaction to produce energy. It takes the chain reaction to produce energy in a good way

Question 22

parts of a nuclear reactor

Answer 22

• Fission in the fuel rods generates heat.
• The coolant absorbs this heat and carries it to the steam generator.
• The steam drives the turbine, generating electricity.
• The control rods regulate the reaction to maintain safe and steady energy production.
• The containment structure ensures safety by preventing radiation leakage.

Question 23

atomic mass

Answer 23

larger number at the bottom EX: carbon is 12.01

Question 24

mass number

Answer 24

protons+ neutrons = mass number the isotope name tells you the mass number EX: carbon-14 mass number is 14

Question 25

emits and alpha particle

Answer 25

elemnt > remainder + alpha

Question 26

positron

Answer 26

0/+1 e

Question 27

electron capture

Answer 27

element + 0/-1 e > new element