Atoms & Radioactivity

Question 1

5 signs of chemical change

Answer 1

Change in color, smell, precipitate, release of energy (heat or light), and bubbles.

Question 2

6 metalloids

Answer 2

Boron, silicon, geranium, antimony, arsenic, and tellurium, forms a staircase pattern on the periodic table.

Question 3

fission

Answer 3

when the nucleus gets deformed and the electrical force overcomes the nuclear force and two more stable atoms are formed, occurs spontaneously. Can be induced by bombarding the nucleus with neutrons. Example- U-238 and U-235 (explosion)

Question 4

fusion

Answer 4

Two light nuclei come together to create one large nucleus. Requires VERY high temperatures. Has no radioactive waste.

Question 5

Symbol, charge, and what stops alpha radiation

Answer 5

Little fishy symbol and 4/2 He (helium nucleus), 2+ charge, and skin or paper stops it.

Question 6

Symbol, charge, and what stops beta radiation

Answer 6

B with a long tail symbol and 0/-1 e (electron), 1- charge, and is stopped by aluminum foil or plastic.

Question 7

Symbol, charge, and what stops gamma radiation

Answer 7

Y with a loopy tail symbol, it is jsut pure energy so there is no equation (happens when excited atoms readjust), and it is stopped by thick lead.

Question 8

critical mass

Answer 8

The amount of fissionable material it takes to get a chain reaction going.

Question 9

plutonium

Answer 9

Can be used besides Uranium to make nuclear power or power plant fuel.

Question 10

half life

Answer 10

The amount of time it takes for a radioactive substance to decay.

Question 11

alchemists

Answer 11

Alchemists led to the scientific method, but not to the ability of turning lead into gold.

Question 12

Georg Stahl

Answer 12

All flammables contain phlogistan (Greek for “set on fire”), and it allows it to burn. Burning causes the loss of phlogistan. Ashes can’t burn because its all gone. Substances should lose mass when they burn if phlogistan is lost.

Question 13

Law of Conservation of Mass

Answer 13

Mass isn’t created or destroyed during chemical or physical reactions, and what goes in must come out.

Question 14

What led to the Law of Conservation of Mass, Law of Definite Proportions, and the Law of Multiple Proportions?

Answer 14

Development of accurate balances in the 1700s.

Question 15

Law of Definite Proportions

Answer 15

A chemical compound has the same element in the same proportions no matter the sample size.

Question 16

Law of Multiple Proportions

Answer 16

If there are two different compounds composed of the same elements, the ratio of mass and number of atoms will be a whole number.

Question 17

Dalton’s Atomic Theory

Answer 17

1. All matter is composed of extremely small particles called atoms.
2. Atoms in a given element are identical; different elements differ.
3. Atoms can’t be subdivided (NOT true), created, or destroyed.
4. Atoms of different elements combine in simple whole number ratios to form chemical compounds.
5. In chemical reactions, atoms can be combined, rearranged, or separated, but not changed.

Question 18

JJ Thompson

Answer 18

Created cathode ray tubes that contained gases at low pressure in glass tubes and passed electrical currents through them. Anode has a positive charge and cathodes have a negative charge. The ray attracted towards positively charged metal plates and repelled by negatively charged plates.

Question 19

Millikan

Answer 19

Determined the mass of an electron to be 1/1,840 of a proton.

Question 20

Goldstein

Answer 20

Used the metallic plates and the cathode ray on Hlittle2 without the electrons and discovered there was a positive charge left.

Question 21

Chadwick

Answer 21

Confirmed the presence of a neutron. Created the plum pudding model, with the electrons incorrectly stuck in the lump of positively charged protons.

Question 22

Rutherford

Answer 22

Created the gold foil experiment. He expected that the alpha particles would not pass through and they would be mildly deflected. The actual result is that most alpha particles passed straight through without deflection, but a few bounced off at large angles. Proved that the vast majority of particles must be empty space.

Question 23

isotopes

Answer 23

Atoms of the same element with different masses. They have a different number of neutrons but the same number of protons. They are chemically similar with different physical properties.

Question 24

Avogadro

Answer 24

Found the number of particles in exactly one mole of a pure substance.

Question 25

Three isotopes of hydrogen:

Answer 25

Protium (one proton), deuterium (one proton and one neutron), and tritium (one proton and two neutrons).

Question 26

radioactivity

Answer 26

The spontaneous decay of an unstable atomic nucleus that results in one or more smaller nuclei and one or more radioactive rays.

Question 27

Nuclear force

Answer 27

Attracts protons and neutrons together and works only over very short distances (almost touching).

Question 28

electrical force

Answer 28

Repulsion of the positively charged protons in the nucleus, and effective over greater distances than the nuclear force.

Question 29

neutrino

Answer 29

A tiny, massless particle that is the subject of all kinds of physics research.

Question 30

metals

Answer 30

2/3 of the periodic table, the entire left side EXCEPT for Hydrogen, stops at the metalloids

Question 31

non-metals

Answer 31

last two rows of the periodic table

Question 32

noble gases

Answer 32

last row of the periodic table

Question 33

alkali earth metals

Answer 33

second row of the periodic table

Question 34

alkali metals

Answer 34

first row of the periodic table EXCEPT for hydrogen

Question 35

halogens

Answer 35

second to last row of the periodic table

Question 36

charge of an ion

Answer 36

more electrons? negative

more protons? positive