chem

Bonding Unit Test

Q. 18

Which formula represents strontium phosphate [Sr3PO8, Sr3(PO4)2, SrPO4, Sr2(PO4)3

Sr3(PO4)2

The observed regilarities in the properties of elements are periodic functions of their

atomic numbers

All phosphorus atoms have the same

atomic number

what is the charge of the nucleus of an oxygen atom

+8

As a chemical bond forms between two hydrogen atoms in a system, energy is released and the stability of the system (decreases, increases, remains the same)

increases

Math of chem quiz #1

last question

which characteristic is a property of molecular substances (good heat conductivity, low melting point, good electrical conductivity, high melting point)

low melting point

Describe the charge and location of an electron in an atom.

negative charge, outside the nucleus

Math of Chem quiz #1

questions 1

Atomic structure Test

questions 16, 19, 20

Math of Chem test

questions 19,21, 23, 24, 25

Which atom in the ground state requires the least amount of energy to remove its valence electrons (Potassium, sodium, rubidium, lithium)

rubidium

atomic radius

size of an atom

At STP, fluorine is a gas and bromine is a liquid because, compared to fluorine, bromine has (Stronger intermolecular forces, weaker covalent bonds, weaker intermolecular forces, stronger covalent bonds)

stronger IMF

Degree of Polarity

-depends upon the electronegativity difference between two bonding atoms -greater the difference, the more polar the bond

How many valence electrons are in an atom of K-42 in the griund state

1

What is the total number of unpaired electrons in an atom of oxygen in the ground state (6, 2, 8, 4)

2

what is the number of electrons in an atom that has 20 protons and 17 neutrons?

20

What is the gram formula mass of Fe(NO3)3 [146, 194, 214, 242g/mol]

242 g/mol

A 100.00-gram sample of naturally occurring boron contains 19.78 grams of boron-10 (atomic mass = 10.01 atomic mass units) and 80.22 grams of boron-11 (atomic mass = 11.01 atomic mass units). Which numerical setup can be used to determine the atomic mass of naturally occurring boron?

(0.1978)(10.01)+(0.8022)(11.01)

What is the charge of the nucleus of a copper atom

+29

What is the maximum number of electrons that can occupy the fourth principal energy level (shell) of an atom? (6, 8, 18, 32)

32

A sample of a substance containing only magnesium and chlorine was tested in a lab and was found to be composed of 74.5% chlorine by mass. If the total mass of the sample was 190.2 grams what was the mass of the magnesium? (142g, 48.5, 24.3, 70.9)

48.5

The percent by mass of water in the hydrate Na2So4•10H20 is closest to (76%, 18%, 44%, 56%)

56%

Math of chem quiz #2

8, last page

A hydrate is a compound that includes water molecules within its crystal structure. During an experiment to dtermine the percent by mass of water in a hydrated crystal, a student found the mass of the hydrated crystal to be 4.10 grams. After heating to constant mass, the mass was 3.70 grams. What is the percent by mass of water in this crystal? (9.8%, 0.40%, 11%, 90%)

9.8%

ionic compound

A compound that consists of positive and negative ions (metal and nonmetal)

polar covalent bond

A covalent bond in which electrons are not shared equally

Explain in terms of charge distribution why a molecule of butanamide is polar

A molecule of Butamide is polar because the charge is not being distributed equally.

Which general trends in atomic radius and electronegativity are observed as the elements in period 3 are considered in order of increasing atomic number? (Both atomic radius and electronegativity decrease, Both atomic radius and electronegativity increase, Atomic radius increases and electronegativity decreases, Atomic radius decreases and electronegativity increases)

Atomic radius decreases and electronegativity increases

Why do the ionization energies increase across each period (left to right)?

Bc of the increase in nuclear charge

Why do the ionization energies decrease down each group?

Bc the amt of electron shells increase

A compound has a molar mass of 90 grams per mole and the empirical formula CH2O. What is the molecular formula of this compound? (CH2O, C2H4O2, C3H6O3, C4H8O4)

C3H6O3

Based on the bond type, which compound has the highest melting point (CaCl2, CCl4, CH3OH, C6H14)

CaCl2 (metals and ionic compounds have high melting points)

Which element has the greatest density at STP (copper, calcium, carbon, chlorine)

Copper

Which atom in the ground state has an outermost electron with the most energy?(Cs, K, Li, Na)

Cs

What is the formula for iron(II) oxide (FeO2, Fe2O, FeO, Fe2O3)

FeO

Explain, in terms of valence electrons, why the bonding in magnesium oxide, MgO, is similar to the bonding in barium chloride, BaCl2

In both, valence electrons are being transferred, making the bonding ionic

Explain, in terms of atomic structure, why thr atomic radius if iodine is greater than the atomic radius of flourine.

Iodine has more occupied electron shells than Flourine

Explain, in terms of subatomic particles, why K-37 and K-42 are isotopes of Potassium

K-37 and K-42 are isotopes of Potassium because they have different amounts of subatomic particles but have the same proton count

An atom of which element has the largest atomic radius (Fe, Mg, Si, Zn)

Mg

In the formula XSO4, the symbol X could represent the element (Ar, Al, Na, Mg)

Mg

Which statement explains why neon is a group 18 element

Neon atoms have a stable valence electron configuration

Which list includes elements with the most similar chemical properties (N,O,F; O,S,Se; Br,Ga,Hg; Cr,Pb,Xe)

O, S, Se

Explain in terms of electron configuration why an oxygen molecule is more stable than an oxygen atom

Oxygen moleculed have atoms with completed octets.

Which atom in the ground state has three half filled orbitals (P, Si, Al, Li)

P

What is the chemical formula for lead (IV) oxide (Pb4O, PbO4, PbO2, Pb2O)

PbO2

ionization energy

The amount of energy required to remove an electron from an atom

State one conclusion about the internal structure of the atom that resulted from the gold foil experiment

The internal structure of the atom is composed of a postively charged nucleus

An atom of an elememt has a total of 12 electrons. An ion of the same element has a total of 10 electrons. Which statement describes the charge and radius of the ion? (The ion is positively charged and its radius is smaller than the radius of the atom, The ion is positively charged and its radius is larger than the radius of the atom, the ion is negatively charged and ita radius is smaller than the radius of the atom, the ion is negatively charged and its radius is larger than the radius of the atom)

The ion is positively charged and its radius is smaller than the radius of the atom

State the model that first included electrons as subatomic particles (Dalton model, Thomson model, Rutherford, Bohr)

Thomson

The gram formula mass of NO2 is defined as the mass of (two moles of NO, one mole of NO2, two molecules of NO, one molecule of NO2)

Two moles of NO

nonpolar bond

a covalent bond in which electrons are shared equally

Explain in terms of both protons and neutrons, why Co-59 and Co-60 are isotopes of cobalt

bc they have the same amt of protons but different amt of neutrons

What is the correct name for the compound with the formula CrPO4 (chromium (II) phosphide, chromium (III) phosphide, chromium (III) phosphate, chromium (II) phosphate)

chromium (III) phosphate

which phrase describes the two forms of phosphorus

different crystal structure and different properties

Down a Group (electronegativity, IE, radius, metallic char) (uptrend, downtrend)

electroneg= decreases I.E.= decreases radius= increases metallic char= increases

Across a period (Electronegativity, Ionization energy, radius, metallic character)

electroneg= increases, Ionization energ= increases, radius= decreases, metallic character= decreases (uptrend, downtrend)

what occurs in covalent compounds

electrons are SHARED

What occurs in ionic compounds

electrons are TRANSFERRED

When an excited electron in an atom moves to the ground state, the electron (absorbs energy as it moves to a higher energy state, absorbs energy as it koves to a lower energy state, emits energy as it moves to a higher energy state, emits energy as it moves to a lower energy state)

emits energy as it moves to a lower energy state

Which element has atoms with the strongest attraction for electrons in a chemical bond? (flourine, oxygen, nitrogen, chlorine)

flourine

intermolecular forces

forces of attraction between molecules

The atomic mass of an element is the weighted average of the atomic masses of

the naturally occuring isotopes of the element

An atom is electrically neutral because

the numbers of protons and electrons are equal

Molecule

two or more atoms held together by covalent bonds