Unit 3 Test

Question 1

Is water a polar or a nonpolar molecule? Why?

Answer 1

Water is a polar molecule because the protons in the oxygen nucleus pull the negative electrons closer to the oxygen end of the molecule, giving it partial negative charge. The hydrogen end of the molecule becomes partially positive because the hydrogen protons are “sticking out.”

Question 2

What happens when a polar and nonpolar solution are combined?

Answer 2

Polar and nonpolar solutions do not mix.

Question 3

What is electronegativity and what is it used for?

Answer 3

Electronegativity is the ability of an atom to attract electrons when the atom is in a compound. It’s used for measure the tendency of an atom to attract bonding pair electrons.

Question 4

How do you know the number of valence electrons in an atom?

Answer 4

The valence electrons are the same as the elements group number.

Question 5

What types of elements are in group 1 and 2 on the periodic table?

Answer 5

The elements in group 1 and 2 are metals.

Question 6

What type of element is hydrogen?

Answer 6

Hydrogen is a nonmetal.

Question 7

Are there any polyatomic cations?

Answer 7

Yes, these are ammonium and hydronium

Question 8

What are valence electrons?

Answer 8

Valence electrons are electrons in the highest occupied energy level of the element’s atoms.

Question 9

What subatomic particle determines an element’s chemical properties?

Answer 9

Valence electrons determine the atom’s chemical properties.

Question 10

When are roman numerals used?

Answer 10

Roman numerals are used when writing formulas for transition metals.

Question 11

What does the octect rule have to do with noble gases?

Answer 11

The goal of the octect rule is to obtain the electron configuration of noble gases because they are stable.

Question 12

What does the charge on an ion represent?

Answer 12

The charge determines whether the ion is positive or negative. If an ion gains electrons it becomes more negative, while if it loses electrons it becomes positive.

Question 13

What does the octect rule state and how does it apply to ionic versus covalent compounds?

Answer 13

The octect rule states that in forming compounds, atoms tend to achieve the electron configuration of a noble gas. In ionic compounds it exchanges electrons while it shares electrons in covalent compounds.

Question 14

what is a salt?

Answer 14

Salt is a chemical compound of sodium and chlorine.

Question 15

what type of ions end in –ide?

Answer 15

Ions that end in –ide are anions.

Question 16

what are the elemental characteristics of ionic compounds compared to covalent compounds?

Answer 16

Ionic compounds are a mix of metals and nonmetals. Covalent compounds consist of 2+ nonmetals.

Question 17

what is the definition of ionic bond?

Answer 17

An ionic bond are electrostatic forces that hold ions together. They are used to create stable octects.

Question 18

how do you know the charge of a transition metal from the formula?

Answer 18

To find the charge of a transition metal from the formula you use the reverse criss-cross method.

Question 19

how can you differentiate between a polar covalent and nonpolar covalent bond?

Answer 19

A polar covalent bond electronegativity ranges from .4-1.9 while nonpolar covalent is 0-.4.

Question 20

which intermolecular force affects the surface tension of a substance?

Answer 20

Hydrogen bonds affect the surface tension of a substance

Question 21

What is a polyatomic ion? What makes it different from an ion?

Answer 21

A polyatomic ion is a tightly bound group of atoms that have covalently bonded positive/ negative charge and behaves as a unit. What makes it different from a regular ion is because it is covalently bonded.

Question 22

What types of molecules have Greek prefixes in their names?

Answer 22

Molecules that are criss-crossed and covalent formulas have Greek prefixes in their names.

Question 23

List all the differences between ionic and covalent compound including their chemical properties (melting points, conductivity, solubility)

Answer 23

Ionic compounds have high melting points, conduct electricity when dissolved in water, and are soluble in polar substances. An example of a ionic compound is salt. Meanwhile, covalent compounds have a low melting point, do not conduct electricity, and are soluble in non-polar substances. An example is sugar.

Question 24

Where are cations vs anions on the periodic table?

Answer 24

Cations are found on the left side of the table in comparison to anions being found on the right.

Question 25

what does it mean when an anion ends -ate or –ite?

Answer 25

When an anion ends in –ate or –ite, it determines how many subscripts it has.

Question 26

How can an acid be identified by its formula?

Answer 26

Based on how an acid is named, it can determine what kind of ion it is. For example, Nitric acid is nitrate and hydrogen. This is because the –ic means the anion ends in –ate.

Question 27

When is the prefix hydro- used as opposed to the ending -ic or -ous in naming acids?

Answer 27

The prefix hydro- is used when the anion ends in –ide. In other words, it is not a polyatomic ion.

Question 28

define ion

Answer 28

when atoms tend to gain/lose electrons based on how many valence electrons they have // atoms or groups of atoms that have a positive/negative charge

Question 29

define cations

Answer 29

(+) ions that have lost electrons, has more positive protons than negative electrons (metals)

Question 30

define anions

Answer 30

(-) ions that have gained electrons has more negative electrons than positive protons (nonmetals)

Question 31

define polar molecules

Answer 31

when one end of the molecule is slightly negative and the other end is slightly positive, this creates a dipole

Question 32

define intermolecular forces / van der waals and name the 3 forces

Answer 32

• weaker than ionic/covalent bonds
• determine whether a compound is a solid, liquid, or gas
• the 3 forces that fall under this category are dipole, interactions, dispersion forces, and hydrogen bonding

Question 33

define dipole interactions

Answer 33

polar molecules are attracted to one another, creates cohesion among the molecules

Question 34

define dispersion forces

Answer 34

extremely weak due to the movement of electrons in a molecule, the more electrons a molecule has = greater dispersion forces

Question 35

define hydrogen bonding

Answer 35

the attractive forces - almost bonding - between Hydrogen atoms of covalent moleculesand an unshared electron paurs of another atom. This creates surface tension

Question 36

name 2 qualities of a polar molecule

Answer 36

• asymmetrical electron distribution

- geometrical symmetry

Question 37

covalent bonds have more or less electronegativity

Answer 37

less

Question 38

true or false: a dipole movement is required for a polar molecule

Answer 38

true

Question 39

where do cohesive molecules pull molecules

Answer 39

inward

Question 40

define halide ions

Answer 40

ions produced when atoms of chlorine and other halogens gain electrons
-all have 7 v.e. and only need one more to achieve an electron configuration of a noble gas

Question 41

define diatomic molecule

Answer 41

molecule consisting of 2 molecules

Question 42

define single covalent bond (same with double and triple covalent bond)

Answer 42

2 atoms that are joined by sharing a pair of electrons

EX: H-H

Question 43

define coordinate covalent bond

Answer 43

covalent bond in which 1 atom contributes both bonding electrons

Question 44

define bond disassociation energy

Answer 44

energy required to break 2 covalently bonded atoms

Question 45

define nonpolar covalent bond

Answer 45

when atoms in a bond pull equally

Question 46

define polar covalent bond

Answer 46

covalent bond between atoms in which the electrons are shared unequally ; the more electronegative atom attracts electrons more strongly and gains a slightly negative charge

Question 47

define dipole

Answer 47

molecule with 2 poles