Chapter 3 Test Flashcards

1
Q

Chemical Bond

A

The attraction between the atoms or ions of a substance

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2
Q

Stable Octet

A

Atoms having 8 valence electrons

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3
Q

How can atoms become stable?

A

It is possible for atoms to acquire a stable octet by the loss or gain of electrons. Atoms could achieve this by sharing electrons between them, that is, by chemically bonding to one another

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4
Q

Ionic Bonding

A

A type of chemical bonding resulting from the attraction between oppositely charged ions formed when metallic atoms transfer electrons to nonmetallic atoms

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5
Q

Physical Properties of Ionic Compounds

A
  1. Solids at room temperature
  2. Poor conductors of electricity when solid, but good conductors when molten
  3. Have high melting and boiling points which indicates strong bonding
  4. Crystalline, hard but brittle
  5. Are often soluble inwater
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6
Q

What happens when an ionic bond is formed?

A

When an ionic bond is formed by electron transfer between a metal and a non-metal,all of the electrons lost by the metal must be gained by the non-metal.

when ionic bonds are formed, enough electrons must be transferred so that each ion produced is isoelectronic with a NOBLE GAS

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7
Q

Covalent Bonding

A

When a pair of electrons is SHARED between 2 atoms

Ex. H• + •H → H••H
(single bond H—H)

  • more bonds = more stable*
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8
Q

Diatomic Molecule

A

Molecules that consist of the same atoms

Ex. H2, N2, O2, F2, Cl2, Br2, I2, At2
HOFBrICI

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9
Q

Lewis Structure

A

A formula in which single lines are used to represent shared pairs of electrons and dots are used to represent valence electrons not involved in bonding

Ex. CI— CI

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10
Q

Physical Properties of Covalent Compounds

A
  1. Exist as gases, liquids and solids at room temperature
  2. Solid covalent compounds are usually soft
  3. Covalent compounds usually evaporate readily
  4. Have low melting and boiling points
  5. Not soluble in polar substances, such as water, but are soluble in nonpolar substances such as gasoline or oil
  6. Do not conduct electricity in either liquid or solid state
    (since they don’t dissociate into ions → no electrolytes→no conduction)
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11
Q

Double Covalent Bond

A

When 2 pairs of electrons are shared between 2 atoms

EX.​O = O

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12
Q

Triple Covalent Bond

A

When 3 pairs of electrons are shared between atoms

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13
Q

Polar Molecule

A

A molecule with a slightly negative and a slightly positive end

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14
Q

Polar Covalent Bond

A

A covalent bond in which there is an unequal sharing of electrons

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15
Q

Electronegativity

A

A quantitative measure of the electron-attracting ability of the atoms in a molecule
→ the higher the #,the higher the electronegativity

it parallels ionization energy

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16
Q

The greater the difference in electronegativity between the 2 atoms involved in a polar covalent bond, the more polar the bond will be

A

EX.

EN CI = 3.0
—
EN H = 2.1
—————— 
△EN = 0.9
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17
Q

What are the 2 factors that determine whether or not a molecule will be polar or non-polar?

A
  1. The polarity of the bonds

2. The arrangement of the bonds in a molecule

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18
Q

Increasing Electronegativity Difference:

Pure Covalent value?
Polar Covalent value?
Ionic value?

A

Pure Covalent: 0 - 0.5

Polar Covalent: 0.5 - 1.7

Ionic: 1.7 - 3.3

19
Q

Octet Rule

A

When atoms combine, bonds form so that each atom finishes with an octet of valence electrons

20
Q

Steps for Lewis Dot Diagram on Covalent Compounds

A
  1. Determine the central atom (the atoms with the most single valence electrons)
  2. Draw Lewis Dot Diagram around the central atom
  3. Pair the single valence electrons between the atoms
  4. Redraw diagram neatly and ensure each atom in the formula follows the octet or duet rule
21
Q

Nomenclature

A

Naming chemical compounds and writing chemical formulas

22
Q

Free State

A

Atoms that are bonded to other atoms of the same element: Diatomic Elements

23
Q

Free Element

A

Atoms that are not combined with other atoms

24
Q

Polyatomic Ions / Oxyanions

A

An ion, which contains 2 or more atoms

  • all ending in -ate*
25
Q

Naming Chemical Compounds Containing Only 2 Elements:

a) POSITIVE MONATOMIC IONS
b) STOCK SYSTEM (MULTIALENCE)

A

a) if the ion has only 1 oxidation #, then the name of the ion is the same as the name of the element

Ex. Na+ → sodium ion

b)if the ion has more than 1 oxidation #, then the name of the ion is the same as the name of the element, however, a ROMAN NUMERAL in brackets is added right after

Ex. Cu2+ → copper (II)

26
Q

Naming Chemical Compounds Containing Only 2 Elements:

BINARY COMPOUNDS CONTAINING HYDROGEN + ANOTHER ELEMENT

A

a)compounds of hydrogen and a NONMETAL Groups 16 and 17 are named by writing the word “hydrogen” followed by the name of the NONMETAL ending in “ide”

EX. HCI → hydrogen chloride

b)compounds of hydrogen and a METAL are named by writing the name of the METAL followed by “hydride”

EX. NaH → sodium hydride

27
Q

Naming Covalent Compounds

A

The less electronegative element is written first followed by y the name of the second element ending in “ide”. In addition, each element is preceded by a prefix, which indicates the number of atoms of that atom
* mono- is not used on the first element name*

EX. As2S3 → diarsenic trisulfide

28
Q

Rules for Naming Oxyanions

A
  1. If the ion contains 1 MORE OXYGEN atom than the common ion→ per___ate
  2. If the ion contains 1 LESS OXYGEN atom →___ite
  3. If the ion contains 2 LESS OXGEN atoms than the common ion → hypo___ite
29
Q

Prefix thio: an oxygen from an oxyanion is replaced by a sulfur

thio___ate → root of common oxyanion ends in ate
thio___ite → root of common oxyanion ends in ite

A

EX. Na3SPO3 = sodium thiophosphate

30
Q

Acid

A
  • is a compound which has a sour taste
  • turns litmus paper red
  • contains at least 1 hydrogen atom that can be replaced by metals
31
Q

What are the 2 groups of acids?

A
  1. Binary Acids:
    H + any anion (non-metal)
  2. Oxyacids:
    H + oxyanion
32
Q

Naming Binary Acids

A

Consists of hydrogen and a NONMETAL from Group 16 or 17. They are named by writing the word “hydrogen” followed by y the name of the NONMETAL ending in “ide”
→ this is for formulas with a (g)
EX. HCI (g) → hydrogen chloride

Solutions of these compounds dissolved in water (aq) are acids. They are named by using the prefix “hydro,” the name of the nonmetal ending in “ic” and followed by the word “acid”
→ this is for formulas with an (aq)
EX. HCI (aq)→ hydrochloric acid

33
Q

Rules for Naming Oxyacids

A
  1. ___ate →___ic acid
  2. per___ ate → per___ic acid
  3. ___ite →___ous acid
  4. hypo___ite → hypo___ous acid
34
Q

Hydrates

A

Compounds containing water of hydration

→when aqueous solutions of many of the soluble salts are evaporated, a precise # of water molecules may be retained as the ions form crystals

35
Q

Rules for Naming Hydrates

A

Name the first part of the formula according to the rules learned in previous lessons followed by a “prefix-hydrate”

EX. MgSO4•7H2O
→ magnesium sulfate• heptahydrates

36
Q

Bases

A

A substance which increases the # of hydroxide ions present in an aqueous solution

→ there will be a hydroxide ion present (OH)

37
Q

Rules for Naming Bases

A

Write the name of the metal followed by “hydroxide”

EX. NaOH → sodium hydroxide

38
Q

How can metals conduct electricity?

Free electrons conduct electricity

A

When a negative and a positive electrode are placed on a metal, the valence electrons move away from the negative electrocode and toward the positive one creating an electric current. Because metal atoms have a small core charge and a large radius, their valence electr ons can move freely and conduct electricity through this electrical current

38
Q

How can metals conduct heat?

Free electrons conduct heat

A

Because valence electrons in metals move freely, they can conduct heat quickly from one end of a metal object to the other

If you heat one end of a metal, the neat gives nearby electrons energy, and the electrons move faster. The rapidly moving electrons move through the metal and collide with the slower/colder electrons farther away, allowing for the metal to conduct heat from one end to the other.

38
Q

How can metals reflect light?

Free electrons reflect light

A

Light is an electromagnetic wave, and when it strikes a metal, it causes free electrons near the surtace to vibrate. This in turn causes the light to change direction, consistent with the laws of reflection

38
Q

How can metals be dented or crushed?

Free electrons permit metals to be dented and crushed

A

Metals can be bent, hammered and stretched because of their small core charges and large radii. This lets metals to be struck without breaking as the atom cores slip into new positions, and the free electrons flow around them.

39
Q

Explain why an ionic compound can conduct electricity but a molecular compound can’t

A

An ionic compound can conduct electricity because it is made up of and dissociates into ions
when it is in the form of an aqueous solution. And in this state, the ions are electrolytes so they can conduct electricity.

Molecular compounds can’t do this because they do not dissociate into ions, meaning there are no electrolytes to conduct electricity.

40
Q

Describe dissolving at a molecular level

A
  1. the ions of an ionic compound dissociate in water
  2. Intermolecular attraction in H20 molecules becomes more distant
  3. H2O molecules hydrate the dissociated ions because of the attraction between the charges