Chem Ch 2

Question 1

Law of definite proportions

Answer 1

All samples of a given compound, regardless of their source or how they are prepared, have the same proportions of their constituent elements.

Question 2

Law of multiple proportions

Answer 2

John Dalton. When two elements (A and B) form two different compounds, the masses of element B that combine with 1 g of elements A can be expressed as a ratio of small whole numbers.

Question 3

Electrostatic forces

Answer 3

Attractive or repulsive forces that an electrically charged particle forms with other charged particles.

Question 4

Electron

Answer 4

Negatively charged, low-mass particle present within all atoms. Mass 0.00055 amu, -1.60 * 10^-19.

Question 5

Radioactivity

Answer 5

The emission of small energetic particles from the core of certain unstable atoms. Alpha, beta, and gamma. Alpha particles are positive and large.

Question 6

Nuclear theory of the atom

Answer 6

Rutherford. Most of the atom’s mass and all of its positive charge are contained in a small core called the nucleus.
Most of the volume of the atom is empty space, throughout which electrons are dispersed.
There are as many negatively charged electrons outside the nucleus as there are positively charged particles within the nucleus.

Question 7

Neutrons

Answer 7

Neutral particles within the nucleus. Mass 1.00866 amu, no charge.

Question 8

Atomic mass unit

Answer 8

amu. 1/12th the mass of a carbon atom containing 6 protons and 6 neutrons.

Question 9

Protons

Answer 9

Positively charged. 1.00727 amu, 1.60 * 10^-19 charge.

Question 10

Atomic number

Answer 10

The number of protons in an atom’s nucleus, symbol Z. Bottom left when written isotope notation.

Question 11

Chemical symbol

Answer 11

1 or 2 letter abbreviation of chemical name

Question 12

Isotope

Answer 12

Atoms with same number of protons but different numbers of neutrons. All atoms of an element do not have the same mass.

Question 13

Natural abundance

Answer 13

Relative amount of each different isotope in a naturally occurring sample of a given element, told in percentages.

Question 14

Mass number

Answer 14

number of neutrons and protons in an atom. Above the atomic number in isotope notation.

Question 15

Ion

Answer 15

Charged particles formed by atoms losing or gaining electrons. Behave differently from the atoms from which they are formed.

Question 16

Cations and anions

Answer 16

Cations are positive ions, anions are negative.

Question 17

Periodic law

Answer 17

When elements are arranged in order of increasing mass, certain sets of properties recur periodically.

Question 18

Metals

Answer 18

Found on the left side and middle of the periodic table. Good conductors, malleable, ductile, shiny, lose electrons during chemical changes.

Question 19

Nonmetals

Answer 19

Upper right of table. Dividing line between metals and nonmetals is zigzag from boron to astatine. Varied state, poor conductors, tend to gain electrons during chemical changes.

Question 20

Metalloids

Answer 20

Lie along zigzag. Semiconductors (intermediate and temperature dependent conductivity). Do not include Aluminium or Po.

Question 21

Main-group elements

Answer 21

Properties tend to be predictable based on position.

Question 22

Transition metals

Answer 22

Properties less predictable. From Sc to Zn.

Question 23

Family or group

Answer 23

Columns within main group regions. Usually have similar properties.

Question 24

Noble gases

Answer 24

Group 8a. Unreactive. Gas.

Question 25

Alkali metals

Answer 25

Group 1a. Reactive metals.

Question 26

Alkaline earth metals

Answer 26

Group 2a. Fairly reactive.

Question 27

Halogens

Answer 27

Group 7a. Reactive nonmetals. Mostly gases or liquids that evaporate into gas.

Question 28

Electron change of main group metals and nonmetals

Answer 28

Main group metals often lose electrons, forming cation with same number of electrons as nearest noble gas.
Main group nonmetals tend to gain electrons, forming anions with the same numbers of electrons as nearest noble gases.

Question 29

Atomic mass and how to calculate

Answer 29

The average mass of all isotopes for an element. X(x percentage) + Y(y percentage) + Z(z percentage).

Question 30

Mole

Answer 30

Amount of material containing 6.022 * 10^23 particles. One mole of anything is 6.022 * 10^23 units of that thing. Equal to the number of atoms in exactly 12 grams of pure carbon-12. 1 mol carbon atoms = 6.022 * 10^23 C atoms.

Question 31

Avagadro’s number

Answer 31

6.022 * 10^23

Question 32

Converting between moles and particles

Answer 32

1mol * (6.022 * 10^23 particles/1 mol)

X particles * 1 mol/(6.022 * 10^23 particles)

Question 33

Molar mass

Answer 33

An element’s molar mass in grams per mole is numerically equal to the elements atomic mass in atomic mass units. The lighter the element, the less mass it takes to make one mole.

Question 34

Volume of a sphere
Surface area of a sphere
Diameter of a circle
Volume of cylinder
SA of cylinder

Answer 34

4/3(pi)(r^3)
4(pi)(r^2)
Pi (r^2)
Pi(r^2)h
2(Pi)r(h) + 2(Pi)(r^2)