Science Qz ch. 9 1 & 2

Question 1

Democritus

Answer 1

proposed matter was made of small particles called atoms.

Question 2

Aristotle

Answer 2

He did not agree with Democritus, he thought all matter was made up of the four elements.

Question 3

Dalton

Answer 3

proved Democritus’s theory true, and made the first atomic theory. Also believed that all matter was made up of atoms that were identical, and every element had a unique type of identical atoms.

Question 4

Thomson

Answer 4

showed that atoms are made of even smaller particles. Discovered negatively charged electrons. Created the chocolate chip cookie model.

Question 5

Rutherford

Answer 5

Tried the gold foil experiment and discovered protons inside the nucleus. Also concluded atoms are made mostly of empty space.

Question 6

Chadwick

Answer 6

discovered neutrons working with rutherford.

Question 7

Bohr

Answer 7

proposed that electrons orbit the nucleus like the solar system, and they farther away the electrons get, the more energy they have.

Question 8

Proton

Answer 8

positively charged particle inside the nucleus

Question 9

neutron

Answer 9

neutrally charged particle in the nucleus.

Question 10

electron

Answer 10

negatively charged particle that orbits the nucleus in layers.

Question 11

Isotopes

Answer 11

atoms of the same element that have different numbers of neutrons.

Question 12

Atomic number

Answer 12

the number of protons in an atom of an element (every substance has a different number of protons)

Question 13

Nuclear decay

Answer 13

a process that occurs when an unstable atomic nucleus changes into another more stable nucleus by emitting radiation.

Question 14

Alpha decay

Answer 14

releases 2 protons and makes the atomic number decrease by 2.

Question 15

Beta decay

Answer 15

a neutron changes into a proton, atomic number increases by 1

Question 16

gamma decay

Answer 16

contains a lot of energy and does not contain particles. Can pass through a thin sheet of lead!