Chapter 2

Question 1

Johann Wilhelm

Answer 1

Discovered that when voltage is applied in a glass tube containing a gas at a low pressure, the cathode emits a beam of cathode rays towards the anode. The glass behind the cathode glowed

Question 2

What are cathode and anodes?

Answer 2

Cathode: Negative electrode

Anode: Positive electrode

Question 3

JJ. Thompson

Answer 3

Discovered electrons(particles in cathode rays) and that cathode rays are deflected by magnetic and electric fields. Cathode rays always behave the same way and have the same mass to charge ratio. The beam from cathode ray tube is deflected toward positively charged plate, away from the negatively charged plate. Made the plum pudding model of the atom where electrons are distributed throughout a diffuse, positively charged amotsphere.

Question 4

Robert Millikan

Answer 4

Advanced Thompson’s work and determined the mass and charge of an electron with his oil drop experiment. Mass=9.109E-28g. Charge=-1.602E-19 C

Question 5

Henri Becquerel

Answer 5

Discovered that some materials produce invisible radiation consisting of charged particles by studying pitchblende

Question 6

What is radioactivity/radiation and what are the types?

Answer 6

Spontaneous emission of high energy radiation and particles. Beta particles are high energy electrons that penetrate solids better and alpha particles have a +2 charge and their mass=He nucleus

Question 7

Rutherford’s gold foil experiment

Answer 7

Rutherford bombarded a thin gold foil with alpha particles to test Thompson’s model of the atom, he did not get expected results. He expected most alpha particles to go through and some get slightly deflected, while most passed through, some were deflected by 90 degrees and same were deflected backwards. This revealed a positively charged nucleus that is much larger than an alpha particle in the middle of the atomic

Question 8

James Chadwick

Answer 8

A student of Rutherford. He bombarded a thin beryllium sheet with alpha particles and a very high energy radiation was emitted by the metal that was not deflected by either electric or magnetic fields. the radiation came from these newly discovered neutrons

Question 9

Unit used to measure atomic distances

Answer 9

picometer(pm) or angstrom(A)

Question 10

Why do we use the unified atomic mass unit instead of the atomic mass unit?

Answer 10

The amu=6protons+6electrons. This was meant to represent the mass of a carbon 12 nucleus but they are not actually equal. Mass of the carbon 12 nucleus+6electrons(1 whole atom)=12u exactly

Question 11

Aston’s experiment

Answer 11

Discovered the existence of isotopes by discovering the 2 different types of neon gas exist. He fired cathode rays at different neon isotopes and discovered different deflection angles

Question 12

Nuclide

Answer 12

an atom(or nucleus) with a specific number of protons and neutrons

Question 13

Average atomic mass

Answer 13

Weighted average of masses of all STABLE isotopes of an element

Question 14

Dmitri Mendeleev

Answer 14

Ordered elements by atomic mass, arranged elements based on similar chemical and physical properties and left open spaces for elements not discovered. He gave a solid foundation for the periodic table we have now

Question 15

Periods

Answer 15

Horizontal rows in the periodic table

Question 16

Families/Groups

Answer 16

Vertical columns in the periodic table that tend to have the same physical and chemical properties

Question 17

Properties of Metals

Answer 17

Shiny solids, conduct heat and electricity, malleable, ductile

Question 18

Properties of Nonmetals

Answer 18

Solids, liquids and gases. Nonconductors, solids nonmetals are brittle

Question 19

Properties of metalloids

Answer 19

Between metals and nonmetals, shiny solids, brittle, semiconductors

Question 20

Alkali Metals

Answer 20

Group one of the periodic table(excluding hydrogen)

Question 21

Alkaline earth metals

Answer 21

Group 2 of the periodic table

Question 22

Halogens

Answer 22

Group 17 of the periodic table

Question 23

Noble/rare gases

Answer 23

Group 18 of the periodic table

Question 24

Law of multiple proportions

Answer 24

The ratio of the two masses of one element that react with a given mass of another element to form two different compounds is the ratio of two small numbers

Question 25

Molecular compounds

Answer 25

Composed of atoms held together in molecules by covalent bonds, composed on nonmetals

Question 26

Covalent bonds

Answer 26

Bond between 2 atoms created by sharing one or more pairs of electrons

Question 27

Ionic compound

Answer 27

Consist of ions formed by transfer of electrons between atoms, held together by electrostatic forces, and are composed of a metal and a nonmetal. Metals form cations and nonmetals form anions

Question 28

Charges of groups 1, 2, and 17

Answer 28

1: +1
2: +2
3: -1

Question 29

Formula unit

Answer 29

Smallest electrically neutral unit of an ionic compound

Question 30

What is special about Mercury and Gallium being classified as metals?

Answer 30

Mercury is liquid at room temperature, Gallium is solid but has a very low melting point as well

Question 31

What is special about At being classified as a metalloid?

Answer 31

It is too unstable to be worked with so it is predicted to be a metalloid

Question 32

Oxoanions

Answer 32

Polyatomic ions containing oxygen in combination with one or more other elements

Question 33

Binary Acids

Answer 33

Contain hydrogen and a monoatomic anion(mostly halogens)

Question 34

Neutron capture

Answer 34

When individual neutrons collide and fuse with atomic nuclei

Question 35

Denotation of hydrogen 2 isotope and it’s name

Answer 35

2D or D, deuterium

Question 36

Name and denotation of hydrogen 3 isotope

Answer 36

3T or T, Tritium

Question 37

Energy of fusion

Answer 37

solid to liquid