Unit 1: Matter, Chemical Trends, and Bonding

Question 1

What are the 3 ways of representing an element?

Answer 1

Example: Sodium

(23 is the mass number and 11 is the atomic number)

1) 23

Na

11

2) Na- 23
3) Sodium - 23

Question 2

What do “A” and “Z” represent?

Answer 2

A= Mass Number

Z= Atomic Number

Question 3

When given that Potassium has 19 protons and 20 neutrons how would you determine A and Z?

Answer 3

Z= 19 (Atomic Number/ Number of Protons)

A= Z + N = 19 + 20 = 39 (Atomic Mass)

Question 4

Isotope

Answer 4

An element which has the same number of protons in all its other forms but a different number of neutrons. They have the same chemical properties but their physical appearance differs. ( Same Z; Different A)

Question 5

What is Heavy Water? What is it’s chemical formula?

Answer 5

Water that contains hydrogen in the form of deuterium.

D₂O

Question 6

Mass Spectrometer

Answer 6

A device used to determine the atomic mass and relative abundance of each isotope present in an element.

Question 7

amu

Answer 7

Atomic Mass Unit

Question 8

Radio Isotopes

Answer 8

Isotopes and are unstable and decay emitting radiation as their nucleus changes.

Question 9

What are the 3 types of radiation, their speed, their penetration distance, and an example of an effective barrier?

Answer 9

1) Alpha Slow, A few cm, and a sheet of paper
2) Beta Fast, A few m, 1-2mm of metal
3) Gamma Very fast, unlimited, 1m of lead or concrete

Question 10

Alpha Particles

Answer 10

A particle composed of 2 protons, 2 neutrons and equivalent to a helium nucleus with a charge of 2+.

Question 11

Beta Particles

Answer 11

A high energy electron with a charge of 1-.

Question 12

What is the concept of Half- Life?

Answer 12

The time taken for half of a radio active atoms to decay in a radioactive substance.

Question 13

What is the concept of Carbon- 14 Dating?

Answer 13

The measurement of a ratio of Carbon- 14 to Carbon- 12 to determine how long and organism has been dead. They compare the normal ratio of a living organisms to a dead one to find the time that has elapsed.

Question 14

What happens when the amount of Carbon-14 in a sample becomes very small?

Answer 14

The Carbon-14 dating method becomes less reliable.

Question 15

What other method can be used to date non-living materials? What is it’s half life?

Answer 15

Potassium-40 is used to date objects too old to be effectively dated by the carbon-14 method. It’s half life is 1.3 X 10⁹ years.

Question 16

What happens to the alkali metals as their atomic number increases?

Answer 16

The elements are more reactive.

Question 17

What is Atomic Radius? List the 2 Facts you need to know about what it does and why it does them.

Answer 17

One half the distance between the nuclei of 2 atoms of the same element.

1) Decreases from left to right across each period on the periodic table. -The atomic number increase by 1 for each element- therefore increasing by 1 proton as we move right. - The attraction between the nucleus and valence electron increases pulling the electron in tighter. (Radius smaller)
2) Increases from top to bottom down each group on the periodic table - The number of valences increases as we go down a group - More valences means more of a shield to attract the valence electrons to the nucleus.

Question 18

What is Ionic Radius? List the 2 facts you need to know about Cations and Anions in terms of their atomic radius.

Answer 18

Cations: 1) Ionic Radius becomes smaller across a period/ row - As a cation looses electrons the ionic radius decreases - The attraction of the electrons to the nucleus increases across a period/ row - The nucleus would be able to pull the electrons closer to the nucleus

Anions: 1) Ionic Radius Increases across a period/ row - When gaining an electron the repulsion among electrons increases while nuclear charge remains the same - Nucleus will not be able to pull the electrons as close to the nucleus - They fill the outer shell therefore radius becomes larger

Question 19

What is Ionization Energy?

Answer 19

The amount of energy required to remove an electron from an atom or ion in the gaseous state.

Question 20

What is the Difference between First Ionization Energy and Second Ionization Energy?

Answer 20

First Ionization Energy: The amount of energy required to remove the most weakly held electron from a neutral atom

Second Ionization Energy: The amount of energy required to remove a second electron from the gaseous positive ion

Question 21

What is Multiple Ionization Energies?

Answer 21

After the first electron is removed the valence shell hets a little closer to the nucleus (Increse in effective nuclear charge) It will now take more energy to remove the 2nd electron.

Question 22

What is Electron Affinity? What is its example equation and its trend?

Answer 22

The energy change that occurs when an electron is accepted by a neutral atom in the gaseous state (Energy will be released).

X(g) + e^-→x^-(g) + Energy

Cl (g) + e^- →Cl^-(g) + 349 kj/mol

Electron Affinity increases across a period (row) and decreases down a group (column)

Question 23

What is Electronegativity? What is it’s trend?

Answer 23

The ability of an atom (When bonded) to attract electrons. The attraction between the valence electrons and the nucleus decreses as the distance between them increases.

Electronegativity increasesacross a period (row) and decreses down a group (coloumn)

Question 24

What is Electrical Conductivity? How does it differ in Ionic and Molecular compounds?

Answer 24

The ability of a material to allow electricity to flow through it. You can use this to determine which kind of compound a substance is.

Ionic Compounds: Form solutions that conduct electricity

Molecular Compounds: Form solutions that don’t conduct electricty

Question 25

Electrolytes vs Non-electrolytes

Answer 25

**Electrolytes:** Substances that form solutions that conduct electricity **Non-Electrolytes:** Substances that form solutions that do not conduct electricity

Question 26

What are the 3 properties of Ionic Compounds?

Answer 26

1) Solids at SATP 2) High Melting and Boiling Points 3) Electrolytes

Question 27

Which groups on the periodic table tend to gain and lose electrons?

Answer 27

Gain: 15, 16, 17 Lose: 1, 2 ,3

Question 28

What are the electrons in a covalent bond doing?

Answer 28

They're being shared

Question 29

Lone pair

Answer 29

A pair of valence electrons not involved in the bonding.

Question 30

Bonding Capacity

Answer 30

The number of covalent bonds (Shared electron pairs) that an atom can form.

Question 31

Electronegativity

Answer 31

The ability of an element to attract one electron.

Question 32

What will happen if one element has a higher electronegativity than the other element it's bonded to?

Answer 32

The electrons will spend more time with the more electronegative element.

Question 33

Polar Covalent Bond

Answer 33

A covalent bond formed between atoms with significantly different electronegativities.

Question 34

The greater distance in electronegativity...

Answer 34

The more polar and ionic the bond becomes.

Question 35

What is the range to decide whether a bond is a) Non-Polar b) Polar Covalent c) Ionic

Answer 35

a) Non-Polar: Difference 0.0 - 0.4 b) Polar Covalent: Anything greater than 0.4 but less than 1.7 c) Ionic: Anything greater than 1.7

Question 36

Ionic Bond

Answer 36

A intramolecular force that involves an electron transfer resulting in the formation of cations and anions which attract eachother.

Question 37

Polar Covalent Bond

Answer 37

An intramolecular force that involves unequal sharing of pairs of electrons between 2 elements. They can involve paris of 1, 2 or 3 (1 being weak and 3 being strong).

Question 38

Non-Polar Covalent Bond

Answer 38

A intramolecular force that involves equal sharing of pairs of electrons. The bonds can have pairs of 1, 2 or 3. (1 being the weakest and 3 being the strongest)

Question 39

**Intra**molecular force

Answer 39

The attractive force within a compound.

Question 40

**Inter**molecular Force

Answer 40

The attractive force between molecules.

Question 41

Are **Intra**molecular or **Inter**molecular Forces Stronger?

Answer 41

**Intra**molecular.

Question 42

van der Waals Forces

Answer 42

Weak intermolecular attractions.

Question 43

What are the 3 van der Waals Forces?

Answer 43

1) Dipole- Dipole 2) London Dispersion Force 3) Hydrogen Bonding

Question 44

Which of the 3 van der Waals Forces is the strongest?

Answer 44

Hydrogen Bonding.

Question 45

Hydrogen Bonds

Answer 45

A relatively strong dipole-dipole force between a positive hydrogen atom of one molecule and a highly electronrgative atom (F, O or N) in another molecule.

Question 46

Cohesion

Answer 46

Water molecules are attracted to one another. they're made up of (-) oxygen and (+) hydrogen atoms. The (+) hydrogens are attracted to the (-) oxygens of the other molecules and vice versa. This attractive force is what gives water its cohesive properties.

Question 47

Surface Tension

Answer 47

The cohesion of water molecules at the surface of a body of water. This forms a "film" or "skin" which strength can be refused by some substances.

Question 48

Adhesion

Answer 48

Forces of attraction between a liquid and another surface

Question 49

What is the Abrieviation for rembering the Acids? What does each bolded word and letter stand for?

Answer 49

**NICK** the **CAMEL** had a **CLAM** for **SUPPER** in **PHOENIX** Each bolded word represents one of the oxyacids. The constants= # of oxygens in the formula The vowels= # of hydrogens in the formula

Question 50

What are the 5 main oxyacids?

Answer 50

1) Nitric Acid 2) Carbonic Acid 3) Chloric Acid 4) Sulphuric Acid 5) Phosphoric Acid

Question 51

What happens when you remove the H's from each word in the acids abbriviation. What does their charge represent?

Answer 51

It creates a "ate" polyatomic ion Example: Nitric Acid (HNO₃) makes Nitrate (NO₃) The charge represents the number of hydrogens in the acid

Question 52

What are the 3 ways we can alter Ions in relation to acids?

Answer 52

1) Adding an oxygen From "ate" → Per\_\_\_\_\_ate Example: Chlorate (ClO₃) → Perchlorate (ClO₄) 2) Removing an oxygen From "ate" → "ite" Example: Chlorate (ClO₃​) → Chlorite (ClO₂) 3) Removing 2 oxygens From "ate" → Hypo\_\_\_\_\_ite Example: Chlorate (ClO₃​) → Hypochlorate (ClO)

Question 53

What are Hydrates? What happens to them when they're heated?

Answer 53

A compound that contains water as a part of its ionic crystal strcuture. When heated, it will decompose to an ionic compound and water vapour when heated.

Question 54

Gamma Rays

Answer 54

Electromagnetic Wavelengths and the most dangerous type of radiation.