Unit 1

Question 1

Characteristics of protons, electrons and neutrons

Answer 1

P - Positive charge, mass of 1, in nucleus
E - Negative charge, 1/2000 the mass of a proton, outside nucleus
N - neutral charge, mass of 1, in nucleus

Question 2

John Dalton

Answer 2

Billard ball model, elements consisted of small, indivisible particles, atoms can’t be created or destroyed

Question 3

JJ Thomson

Answer 3

Plum pudding model, proposed atoms are made of smaller particles, Bulk of atom is positively charge with negative charges scattered around

Question 4

Ernest Rutherford

Answer 4

Gold foil experiment, used radioactive material to fire alpha particles through gold foil, a few rays reflected off, discovering small compact areas containing positive charge, the nucleus

Question 5

Niels Bohr

Answer 5

Nucleus is surrounded by negative electrons

Question 6

Isotopes

Answer 6

Atoms of the same element that don’t have the same number of neutrons, resulting in a different mass. Occurs naturally

Question 7

Isotopic abundance

Answer 7

the relative amount in which each isotope is present, in %

Question 8

Formula for AAM

Answer 8

AAM = (IA#1)(AM#1) + (IA#2)(AM#2)…..

Question 9

Periodic law

Answer 9

Chemical and physical properties of elements repeat in a regular periodic pattern when they are arranged by atomic number

Question 10

Groups vs Periods

Answer 10

G - Vertical
P- Horizontal

Question 11

Alkali metals

Answer 11

G1, very reactive metals, soft, shiny

Question 12

Alkaline earth metals

Answer 12

G2, reactive metals, shiny, good conductors

Question 13

Halogens

Answer 13

G17, very reactive nonmetals, offense gasses, poor conductors

Question 14

Noble Gases

Answer 14

G18, nonmetals, unreactive

Question 15

Ions

Answer 15

Every atom wants to be stable by having a full valence shell. Cations are usually metals and positive, Anions are usually nonmetals and negative

Question 16

Electromagnetic spectrum

Answer 16

light energy that travels in the form of waves

Question 17

Light wave properties

Answer 17

Frequency - the number of cycles per second
Wavelength - the distance between successive crests or troughs in a wave (nanometers)

Question 18

Spectroscopy

Answer 18

Branch of science, light is used to identify / quantify substances by observing the emission spectra

Question 19

Why atoms release light

Answer 19

Electrons gain energy, jump to a higher level and are excited, spontaneously jump down and release energy as light. The distance between each electron is different in each atom which is why each spectra is different

Question 20

Periodic trends

Answer 20

• Reactivity
• Atomic Radius
• Ionic radius
• Ionization energy
• Electron affinity
• Electronegativity

Question 21

Reactivity

Answer 21

The chances a substance will undergo a chemical reaction. More reactive moving towards the right and left edges (except noble gases), metals are more reactive going down, nonmetals going up.
Reactivity increases outwards since elements are closer to having a fuller shell, metals reactivity increases down since electrons are further from protons so they’re easier to remove, nonmetals going up since electrons are closer and easier to attract

Question 22

Atomic Radius

Answer 22

The size of a neutral atom. Increases from top to bottom since electrons are added to new energy level. Decreases from left to right since protons have stronger attraction with there being more added

Question 23

Ionic radius

Answer 23

Size of a charged ion. Increases down since more electron orbitals are added. Decreases left to right since cations on left lose electrons and anions on the right add electrons which increases size

Question 24

Ionization energy

Answer 24

Minimum energy to remove most loosely bound electron in gas phase. Increases from bottom to top and from left to right. (OPPOSITE to atomic size). In smaller atoms, elecrons are closer to nucleus, needing more energy to remove

Question 25

Electron affinity

Answer 25

Energy change when an atom gains an electron. Increases up since electrons are closer to nucleus, meaning more energy is gained when an electron is added. Increases left to right since atom size is smaller

Question 26

Electronegativity

Answer 26

Ability of an atom to attract electrons. Increases up since atomic size decreases, which makes electrons closer to nucleus. Increases left to right since atomic size decreases

Question 27

Isoelectric

Answer 27

Having the same number of electrons per atom, ion, or molecule

Question 28

Ionic vs Covalent compounds

Answer 28

covalent are made of molecules, two nonmetals, insoluble, softer, poor conductors, low melting point Ionic is one metal + one nonmetal, soluble, hard, good conductors, high melting point

Question 29

Diatomic molecules

Answer 29

Two identical atoms joined with a covalent bond. Form a 7

Question 30

Polyatomic ion

Answer 30

Consists of a stable group of several atoms acting together as a single charged particle

Question 31

Hydrates

Answer 31

compound that has absorbed water molecules and included in structure

Question 32

Acid and Base properties

Answer 32

Acid - starts with H, high reactivity, covalent bond, aq state Base - contains OH, high reactivity, ionic bond, aq state

Question 33

Acid vs Base

Answer 33

Acids ionize in water to form free H ions(Ionize - neutral molecule is converted to an ion) Acids are proton donators Bases dissociate in water to produce OH ions (dissociate - ionic compound separating into ions) Bases are proton acceptors

Question 34

pH scale

Answer 34

Measures how acidic or basic a substance is pH is based on hydrogen ion concentration 0 is strongest acid 14 is strongest base 7 is neutral Each step on the pH scale is a tenfold change in acidity

Question 35

2 types of acids

Answer 35

Binary acids two elements only No oxygen hydro prefic Oxyacids More than two elements contains oxygen polyatomic group

Question 36

Polar covalent bond

Answer 36

Covalent bonds aren't always shared equally. A difference in electronegativity results in a polar covalent bond, where there is an equal sharing of electrons

Question 37

Determining polar bonds

Answer 37

0 - 0.4 = nonpolar covalent bond 0.5-1.8 = polar covalent bond 1.9+ = ionic bond

Question 38

Water

Answer 38

Water is a polar molecule Oxygen atom pulls on the shared electrons in each hydrogen causing a partial positive charge on each hydrogen and a partial negative charge on the oxygen Waters polar molecules are so powerful they have their own name: Hydrogen bonds. The special forces between molecules are called intermolecular forces

Question 39

Polar molecules

Answer 39

Polar molecules have slightly charged ends like polar bonds To be classified as a polar molecules, the compound must have polar bonds and an asymmetrical shape

Question 40

Inter vs intramolecular forces

Answer 40

Inter - forces between molecules Intra - bonds within molecules