Chemistry - Compounds

Question 1

What is the atomic theory

Answer 1

• atoms are the smallest part of an element
• composed of 3 subatomic particles: protons, electrons, neutrons
• protons and neutrons make up 99.9% of an atoms mass
• electrons surround the nucleus and make up 99.9% of the volume

Question 2

Do electrons closer or further from the nucleus have more energy

Answer 2

further, harder for the atom to hold

Question 3

what are valence electrons

Answer 3

electrons is the outer energy level

Question 4

How do you format an energy level diagram (top to bottom)

Answer 4

—3e— (# of electrons in each shell)
—2e—

5p (in circle) (# of protons)
6n (# of neutrons)

B (symbol of element or ion)

Question 5

Are groups or periods vertical in the periodic table

Answer 5

groups

Question 6

What are the four main groups in the periodic table

Answer 6

Alkali metals (group 1): soft, shiny, silver in colour, highly soluble and reactive in water.

Alkaline-earth metals (group 2): shiny and silver, but not as soft or soluble as group 1.

Halogens (group 17): poisonous and highly reactive.

Noble gases (group 18): very unreactive due to complete valance shells.

Question 7

What are the three categories of elements in the periodic table

Answer 7

Metals are silver or grey in colour, shiny, malleable, ductile, good conductors of heat and electricity, and most are solid at room temperature; found to the left of the staircase.

Non-metals may be solid, liquid, or gas, and are poor conductors of heat and electricity; found to the right of the staircase.

Metalloids have properties that are intermediate between metals and non-metals.

Question 8

What are isotopes

Answer 8

• Atoms of the same element that contain different amounts of neutrons, and therefore have a different mass number
• The atomic molar mass on the periodic table is an average of all of the element’s isotopes
• The most common isotope of each element is found by rounding the mass number found on the periodic table.

Question 9

What is ionization

Answer 9

the process in which an atom gains or loses and electron to form an ion

Question 10

What is a cation

Answer 10

positively charged ion that forms when an atom loses one or more electron

E.g. a sodium ion loses an electron giving it a 1+ charge – now called a sodium ion and written as Na+.

If the ion has more than one possible charge, indicate the charge in roman numerals after the name – e.g. Ni2+ is called a nickel(II) ion

Question 11

What is an anion

Answer 11

negatively charged ion that forms when an atom gains one or more electrons

a chlorine atom gains one electron giving it a 1- charge – now called an chloride ion and written as Cl-.

Question 12

How are ionic compounds formed

Answer 12

electrons transfer from one atom to another so each atom has a complete valence energy level
The cation and anion are attracted to one another by charge, forming a neutral ionic compound joined by an ionic bond.

Question 13

What are multivalent elements

Answer 13

atoms with more that one stable ion charge, the most common is the first charge listed on the periodic table

Question 14

What are Polyatomic ions

Answer 14

made of several non-metallic atoms joined by covalent bonds

Question 15

What are the properties of ionic compounds

Answer 15

• might melting point and solid at room temp (attraction is strong and continuous)
• Crystalline structure
• solubility in water (each individual ion is attracted to the different end of water molecules)
• Form electrolytic solutions (dissociate into ions, the greater the concentration of ions, the greater the conductivity)

Question 16

What are covalent bonds

Answer 16

• forms when atoms share a pair of valence electrons to make them stable
• results in the simultaneous attraction of nuclei for shared electrons

Question 17

What is a molecule

Answer 17

an independent unit of fixed numbers of non-metallic atoms held together by covalent bonds

Question 18

What are the two types of molecular elements

Answer 18

DO NOT EXIST AS SINGULAR ATOMS

Diatomic elements - composed of 2 atoms
Polyatomic elements - composed of many identical atoms

Question 19

What is the chemical formula of ammonia

Answer 19

NH3(g)

Question 20

What is the common name of C6H12O6(s)

Answer 20

glucose

Question 21

What is the common name of H2O2(l)

Answer 21

hydrogen peroxide

Question 22

What is the chemical formula for sucrose

Answer 22

C12H22O11(s)

Question 23

what is the chemical formula of methane

Answer 23

CH4(g)

Question 24

what is the common name of C2H6(g)

Answer 24

ethane

Question 25

what is the common name of C3H8(g)

Answer 25

propane

Question 26

what is the chemical formula of methanol

Answer 26

CH3OH(l)

Question 27

what is the chemical formula of ethonal

Answer 27

C2H5OH(l)

Question 28

what are the properties of molecular compounds

Answer 28

Form non-electrolytic solutions – molecular compounds do not dissociate into ions.
Low solubility – most are not soluble in water.
Relatively low melting and boiling points –tend to have weak intermolecular forces (between molecules).
Require large amounts of energy to decompose – indicates that covalent bonds (intramolecular forces) within the molecule are strong.
Molecular substances can form crystals like ionic compounds, but they crumble easily.

Question 29

What makes water a polar molecule

Answer 29

• electrons are shared unequally
• has a slightly positive and negative side
• each end attracts other water molecules to form hydrogen bonds

Question 30

What unique properties are the result of water’s polarity and hydrogen bonding

Answer 30

• high melting and boiling point
• ability of absorb and release lare amounts of thermal energy with small temp changes
• ice floats on liquid water
• high surface tension
• concave meniscus and capillary action - cohesive and adhesive properties
• universal solvent - pos and neg sides are attracted to other substances

Question 31

How do you determine the state of molecular compounds

Answer 31

smaller molecules tend to be gases and larger ones are liquid or solid

Question 32

How do you determine the state of ionic compounds

Answer 32

solid at room temp and pressure

Question 33

How do you determine the state of ionic compounds in an aqueous solution

Answer 33

USE CHART THINGY
If the compound is very soluble then the state is aqueous.
If the compound is only slightly soluble then the state is solid.

Question 34

what does pH measure

Answer 34

concentration of hydrogen atoms in a solution
lower the number the more acidic and higher number is basic

Question 35

What are acid-base indicators

Answer 35

chemicals that change colour depending on the pH of the solution – e.g. litmus paper, phenolphthalein.

Question 36

What are the properties of acids

Answer 36

• sour
• reacts to metals to produce hydrogen gas
• pH under 7
• conducts electricity
• red litmus
• neutralized by bases

Question 37

What are the properties of bases

Answer 37

• bitter
• slippery
• pH over 7
• conducts electricity
• blue litmus
• neutralized by acids

Question 38

How do you recognize an acid

Answer 38

• look for hydrogen symbol on the left or COOH on the right
• ionize in water to release hydrogen ions
• compounds only become acidic when in an aqueous environment

Question 39

What are the naming rules for acids

Answer 39

hydrogen ________ide. –> hydro_________ic acid
eg. hydrogen chloride. hydrochloric acid HCl(aq)
HCl(g)

hydrogen ________ate.–> _____________ic acid
eg. hydrogen chlorate. chloric acid HClO3(aq)
HClO3(s)

hydrogen ________ite. –>. _____________ous acid
eg. hydrogen chlorite. chlorous acid HClO2(aq)
HClO2(s)

Question 40

How do you recognize a base

Answer 40

hydroxide OH