A) melting point

B) mass

C) flammability

D) volume

 A) heat.

B) air.

C) water.

D) salt.

Which of the following is a physical property?

A) flammability

B) conductivity

C) ability to support combustion

D) corrosiveness

Which is an example of matter?

A) electrical current

B) conductivity

C) reactivity

D) plastic

A) the rusting of iron

B) the condensation of water vapor

C) the baking of a potato

D) the explosion of nitroglycerin

Which of the following causes a chemical change?

A) winding an alarm clock

B) metabolizing fat

C) slicing a tomato

D) digging a hole

Chemistry is important to the study of which of the following subjects?

A) Geology

B) Biology

C) Astronomy

D) Physics

E) All of these

A chemist is given an unknown sample. Which observation is not a physical property?

A) The sample is a colorless liquid.

B) The sample has an odor similar to gasoline.

C) The sample is flammable.

D) The sample size is 55 mL.

Which best describes the size and shape of a sample of gas?

A) It has definite volume and definite shape.

B) It has definite volume, but shape is determined by the container.

C) Its volume is determined by the container, but it has a definite shape.

D) Volume and shape are both determined by the container.

A) amount

B) color

C) density

D) odor

E) temperature

Which of the following are states of matter?

A) solid

B) suspension

C) solution

D) precipitate

Which of the following is a pure substance?

A) root beer

B) bleach

C) eggs

D) gasoline

E) neon

A pure substance

A) always has the same elemental composition.

B) is composed of more than one element.

C) can be broken into its components by physical means.

D) is chemically inert.

A) cough syrup

B) iron

C) helium

D) sodium hydrogen carbonate

Each symbol denotes an element except 

A) Co.

B) CO.

C) Cu.

D) C.

A) fire

B) iron

C) salt

D) water

E) wine

What is the chemical symbol for chlorine?

A) C

B) Ca

C) Cl

D) Cr

What is the chemical symbol for calcium?

A) C

B) Ca

C) Cl

D) Cr

A) C

B) Ca

C) Cl

D) Cr

A) C

B) Ca

C) Cl

D) Cr

The most common element by mass percent in the human body is

A) carbon.

B) hydrogen.

C) oxygen

D) sulfur.

Xylene, a compound with the formula C8H10, is composed of

A) any combination of atoms of carbon and hydrogen in a four to five ratio.

B) eight atoms of carbon and ten atoms of hydrogen.

C) eight atoms of calcium and ten atoms of helium.

D) ten atoms of carbon and eight atoms of hydrogen.

Which symbol does not denote a compound?

A)

CO2

B) CCl4

C) C2H4

D) Cr

E) CaCO3

) Which element is not essential for human life?

A) C

B) H

C) P

D) Pb

E) Ca

What is the symbol for tungsten?

A) W

B) Tu

C) Sn

D) St

What element is represented by the chemical symbol K?

A) kaolin

B) phosphorus

C) potassium

D) silver

What element is represented by the chemical symbol Ag?

A) argon

B) arsenic

C) gold

D) mercury

E) silver

Of the elements listed, the most abundant by mass percent in the earth's crust is

A) silicon.

B) aluminum.

C) hydrogen.

D) iron.

The formula for ammonia, NH3, represents a compound composed of

A) one atom of nickel and three atoms of hydrogen.

B) one atom of nitrogen and three atoms of hydrogen.

C) three atoms of nitrogen and three atoms of hydrogen.

D) three atoms of nitrogen and one atom of hydrogen.

The formula for sodium carbonate, Na2CO3, represents a compound composed of

A) two atoms of sodium, three atoms of carbon, and three atoms of oxygen.

B) two atoms of sodium, one atom of carbon, and three atoms of oxygen.

C) six atoms of sodium, two atoms of carbon, and six atoms of oxygen.

D) one atom of sodium and one atom of carbonate.

The formula for glucose, C6H12O6, represents a compound composed of

A) six atoms of carbon, twelve atoms of hydrogen, and six atoms of oxygen.

B) six atoms of carbon, ten atoms of hydrogen, and four atoms of oxygen.

C) one atom of carbon, two atoms of hydrogen, and one atom of oxygen.

D) six atoms of carbon and six atoms of water.

Which chemical symbol represents a non-metal?

A) Al

B) B

C) Ga

D) Si

E) P

Which chemical symbol represents a metallic element?

A) Ar

B) Br

C) Ca

D) H

Which chemical symbol represents a metalloid?

A) Al

B) B

C) Ga

D) Zn

A) 10-3

B) 10-2

C) 10-6

D) 103

The measurement most likely to describe the amount of pain reliever in a headache tablet is

 A) 1.5 kg.

B) 500 mg.

C) 1.00 mL.

D) 325 mg/mL.

Which measurement represents the largest quantity?

A) 4730 ng

B) 4.73 × 10-4 g

C) 4.73 × 103 μg

D) 4.73 × 10-6 kg

E) 47.3 mg

Which measurement represents the smallest quantity?

A) 2950 ng

B) 2.95 × 10-4 g

C) 2.95 × 103 μg

D) 2.95 × 10-6 kg

 Which of the following measurements has three significant figures?

A) 1,207 g

B) 4.250 g

C) 0.006 g

D) 0.0250 g

What is the numerical value of 1.2 × 1.222? Express your answer using the correct number of significant figures.

A) 1.5

B) 1.47

C) 1.466

D) 1.4664

Which of the following numbers contains four significant figures?

A) 230,110

B) 23,011.0

C) 0.23010

D) 0.0230100

E) 0.002301

What is the area of a piece of metal foil that measures 43.9 cm by 29.21 cm? Express the answer to the correct number of significant figures.

A) 128 cm2

B) 1280 cm2

C) 1282.3 cm2

D) 1282.32 cm2

 In scientific notation, the number 185,000,000 is

A) 185 × 106.

B) 1.85 × 106.

C) 1.85 × 108.

D) 185 × 10-8.

 In scientific notation, the number 0.0046 is expressed as

A) 46 × 10-3.

B) 4.6 × 10-3.

C) 4.6 × 10-2.

D) 4.6 × 10-1.

What is 0.0970 written in scientific notation?

A) 970 × 10-4

B) 97 × 10-3

C) 9.70 × 10-2

D) 97.0 × 10-2

 How many centimeters are contained in 12.5 inches?

A) 4.92 cm

B) 5.10 cm

C) 31.8 cm

D) 492 cm

A) 4.92 cm

B) 5.10 cm

C) 31.8 cm

D) 492 cm

How many grams are contained in 1.20 pounds?

A) 545 g

B) 378 g

C) 264 g

D) 2.2 g

How many quarts are contained in 450. mL?

A) 0.426 quart

B) 2.10 quarts

C) 426 quarts

D) 475 quarts

E) 0.475 quarts

How many pounds are contained in 84.0 kg?

A) 0.038 lb

B) 0.084 lb

C) 38.0 lb

D) 185 lb

68°C is the same as

A) 341 K.

B) 321 K.

C) 285 K.

D) 205 K

What temperature is 325 K on the Celsius scale?

A) 52°C

B) 126°C

C) 344°C

D) 598°C

95.0°F is the same as

A) 21°C.

B) 35°C.

C) 85°C.

D) 171°C.

What temperature is 75°F on the Kelvin scale?

A) 24 K

B) 43 K

C) 215 K

D) 297 K

What is the specific heat of a metal if it takes 26.5 calories to raise the temperature of a piece weighing 50.0 g by 5.00 Celsius degrees?

A) 250 cal/g °C

B) 133 cal/g °C

C) 6.63 cal/g °C

D) 1.89 cal/g °C

E) 0.106 cal/g °C

What is the specific heat of a metal if it takes 48.4 calories to raise the temperature of a 45.0 g sample by 5.0°C?

A) 0.186 cal/g °C

B) 0.215 cal/g °C

C) 5.34 cal/g °C

D) 225 cal/g °C

A 35.0 mL sample of a liquid weighs 27.2 g. What is the density of the liquid?

A) 62.2 g/mL

B) 7.80 g/mL

C) 1.29 g/mL

D) 0.952 g/mL

E) 0.777 g/mL

What is the mass of 30.0 mL of a solution with a density of 1.60 g/mL?

A) 53.3 g

B) 48.0 g

C) 31.6 g

D) 18.8 g

A 2.36 cm3 sample of an unknown metal weighs 18.5 g.  What is the sample's density?

A) 7.84 g/cm3

B) 0.127 cm3/g

C) 15.75 g /cm3

D) 0.784 g/cm3

.  The smallest amount of an element that retains that element's characteristics is the

A) atom.

B) electron.

C) molecule.

D) neutron.

E) proton.

Another name for atomic mass unit (amu) is the

A) avogadro.

B) dalton.

C) Kekule

D) kelvin.

E) mendeleev.

.  Which characteristics correctly describe a proton?

A) approximate mass 1 amu; charge +1; inside nucleus

B) approximate mass 5 × 10-4 amu; charge -1; outside nucleus

C) approximate mass 5 × 10-4 amu; charge +1; inside nucleus

D) approximate mass 1 amu; charge 0; inside nucleus

E) approximate mass 1 amu; charge +1; outside nucleus

 Which particle has a mass approximately equal to the mass of a proton?

A) atom

B) electron

C) neutron

D) nucleus

E) quark

.  Protons possess a ________ charge, and neutrons possess a ________ charge.

A) negative, negative

B) negative, positive

C) positive, negative

D) positive, zero

E) zero, positive

Protons possess a ________ charge, and electrons possess a ________ charge.

A) negative, negative

B) negative, positive

C) positive, negative

D) positive, zero

E) zero, positive

In a neutral atom the number of ________ is equal to the number of ________.

A) protons, electrons

B) protons, neutrons

C) neutrons, electrons

D) protons + electrons, neutrons

E) none of the above

Where is most of the mass of an atom concentrated?

A) electrons

B) neutrons

C) nucleus

D) orbitals

E) protons

An atom with Z = 26 and A = 58 contains ________ protons and ________ neutrons.

A) 26; 58

B) 58; 26

C) 26; 32

D) 32; 26

E) 26; 84

  An atom with Z = 35 and A = 80 contains ________ protons, ________ electrons, and ________ neutrons.

A) 35; 35; 80

B) 80; 35; 35

C) 35; 35; 45

D) 45; 80; 45

E) 45; 80; 35

 How many neutrons does an atom of [image]Ti have?

A) 0

B) 22

C) 24

D) 46

E) 68

The symbol of the element with 23 protons is

A) Mg.

B) Na.

C) V.

D) B.

E) none of the above

An atom that contains 47 protons, 47 electrons, and 60 neutrons is an isotope of

A) Ag.

B) Al.

C) Nd.

D) Bh.

E) cannot be determined from the information given

Cobalt is element 27.  Cobalt-60 is used in the medical treatment of cancer.  How many neutrons and protons are contained in the nucleus of this isotope?

A) 27 neutrons, 33 protons

B) 33 neutrons, 27 protons

C) 27 neutrons, 27 protons

D) 33 neutrons, 33 protons

An imaginary element Xq consists of two isotopes having masses of 100.0 amu and 102.0 amu. A sample of Xq was found to contain 20.0% of the 100Xq isotope and 80.0% of the 102Xq. Calculate the atomic weight of Xq.

A) 100.2 amu

B) 100.4 amu

C) 101.0 amu

D) 101.6 amu

E) 202.0 amu

An imaginary element Xz consists of two isotopes having masses of 100.0 amu and 102.0 amu. A sample of Xz was found to contain 75.0% of the 100Xz isotope and 25.0% of the 102Xz. Calculate the atomic weight of Xz.

A) 100.3 amu

B) 100.5 amu

C) 101.0 amu

D) 101.5 amu

E) 101.8 amu

Which elements all belong in the same group?

A) C, N, O

B) Fe, Cu, Ni

C) B, Si, As

D) F, Cl, Br

E) Al, Ge, Sb

 Elements in the Periodic Table are arranged according to

A) alphabetical order.

B) atomic number.

C) atomic weight.

D) date of discovery.

Which element is not a semimetal?

A) Al

B) Si

C) Ge

D) As

E) none of the above

Which group of elements contains only non-metals?

A) Mg, Ca, Sr

B) V, Cr, Mn

C) Cl, Ar, K

D) P, As, Se

E) C, S, I

 Which of the following is an alkali metal?

A) Al

B) Cl

C) He

D) Na

E) O

Magnesium is an example of a(an)

A) alkali metal.

B) alkaline earth.

C) halogen.

D) noble gas.

E) transition metal

Which of the following elements is a noble gas?

A) Cl

B) H

C) N

D) Ne

E) O

Which group contains only metalloids?

A) Ni, Pd, Pt

B) Si, Ge, As

C) Ce, Pr, Nd

D) Kr, Xe, Rn

E) Po, Fr, Ac

Which group contains only noble gases?

A) Ni, Pd, Pt

B) Si, Ge, As

C) Ce, Pr, Nd

D) Kr, Xe, Rn

Which column of the periodic table contains only nonmetals?

A) 4A

B) 5A

C) 6A

D) 7A

 Which element is most likely to have chemical properties similar to those of bromine (atomic number 35)?

A) S (atomic number 16)

B) Se (atomic number 34)

C) Kr (atomic number 36)

D) Te (atomic number 52)

E) I (atomic number 53)

 How many electrons can occupy the shell having n = 2?

A) 2

B) 6

C) 8

D) 18

How many electrons can occupy the shell having n = 4?

A) 2

B) 8

C) 10

D) 18

E) 32

How many electrons can occupy the 4s subshell?

A) 1

B) 2

C) 6

D) 8

E) 10

How many electrons can occupy the 4d subshell?

A) 1

B) 2

C) 6

D) 8

E) 10

At maximum, an f subshell can hold ________ electrons, a d subshell can hold ________ electrons and a p subshell can hold ________ electrons.

A) 14, 10, 6

B) 2, 8, 18

C) 18, 8, 2

D) 2, 12, 21

E) 14, 6, 10

 What is the electron configuration of S?

A) 1s2 2s2 2p2

B) 1s2 2s2 2p6 3s2 3p2

C) 1s2 2s2 2p6 3s2 3p4

D) 1s2 2s2 2p6 3s2 3p6

E) 1s2 2s2 2p6 3s2 3p6 4s2 3d1

What is the electron configuration of Mg?

A) 1s2 2s2 2p8

B) 1s2 2s2 2p6 3s2

C) 1s2 2s2 2p6 3s1 3p3

D) 1s2 2s2 2p6 3s2 3p6 4s2 3d5

E) none of the above

The element with the electron configuration 1s2 2s2 2p4 is ________.

A) Be

B) C

C) O

D) Si

E) S

What is the electron configuration of Fe?

A) 1s2 2s2 2p6 3s2 3p6 3d8

B) 1s2 2s2 2p6 3s2 3p6 4s2 3d6

C) 1s2 2s2 2p6 3s2 3p6 4s2 4p6

D) 1s2 2s2 2p6 3s2 3p6 4s2

E) 1s2 2s2 2p6 3s2 3p6 3d6

 The ground state electron configuration for nickel is

A) 1s2 2s2 2p6 3s2 3p6 3d10.

B) 1s2 2s2 2p6 3s2 4s2 3d10 4p4.

C) 1s2 2s2 2p6 3s2 3p6 4s2 4d8.

D) 1s2 2s2 2p6 3s2 3p6 4s2 3d8.

 The element with the electron configuration 1s2 2s2 2p6 3s2 3p5 is

A) fluorine.

B) chlorine.

C) carbon.

D) potassium.

E) sulfur.

The number of valence electrons in an element with electron configuration

1s2 2s2 2p6 3s2 3p4 is ________.

A) 2

B) 4

C) 6

D) 8

E) 16

The electron configuration for phosphorus is

A) 1s2 1p6 2s2 2p5.

B) 1s2 2s2 2p6 3p5.

C) 1s2 2s2 2p6 3s4 3p1.

D) 2s2 2p6 3s2 3p5.

E) 1s22s22p63s23p3.

The number of valence electrons in a main group element is given by ________.

A) the element's atomic number

B) the element's atomic weight

C) the element's group number

D) none of the above

Valence electrons in the main group elements are contained in which type(s) of orbitals?

A) s

B) p

C) s and p

D) d

How many electrons are there in the valence shell of a nitrogen atom?

A) 0

B) 2

C) 3

D) 5

E) 7

 The element which has four valence electrons is ________.

A) H

B) Na

C) Mg

D) Si

A positively charged particle formed by loss of one or more electrons from an atom is called a(an)

A) anion.

B) cation.

C) isotope.

D) nucleus.

E) proton.

A small negatively charged particle formed when an atom gains one or more electrons is called a(an)

A) anion.

B) cation.

C) isotope.

D) nucleus.

E) proton.

When an atom donates an electron, that electron

A) is lost for all time.

B) is acquired by another atom which becomes an anion.

C) is acquired by another atom which becomes a cation.

D) neutralizes a proton to form a neutron.

E) pairs with another electron to form a covalent bond.

Main group elements that are metals usually ________ one or more electrons to form ________, which have a ________ charge.

A) lose; anions; negative

B) lose; cations; negative

C) lose; cations; positive

D) gain; cations; positive

E) gain; anions; negative

Main group elements that are non-metals usually ________ one or more electrons to form ________, which have a ________ charge.

A) lose; anions; negative

B) lose; cations; negative

C) lose; cations; positive

D) gain; cations; positive

E) gain; anions; negative

One characteristic of a cation is that

A) it has more protons than electrons.

B) it has equal numbers of protons and electrons.

C) it has more electrons than protons.

D) the number of neutrons is related to the number of electrons.

E) the relationship between protons and electrons varies with the cation in question.

The property that describes the ease with which an atom gives up an electron to form a positive ion is

A) atomic number.

B) electron affinity.

C) electronegativity.

D) ionization energy.

E) none of the above

The property defined as the energy released on adding an electron to an isolated gas phase atom is

A) atomic number.

B) electron affinity.

C) electronegativity.

D) ionization energy.

E) none of the above

Which of the following has the largest ionization energy?

A) Ne

B) Br

C) P

D) Al

E) Ca

The property defined as the energy required to remove one electron from an atom in the gaseous state is

A) atomic number.

B) electron affinity.

C) ionization energy.

D) electronegativity.

E) none of the above

An element belonging to the halogen family would be expected to have a ________ ionization energy and a ________ electron affinity.

A) large; large

B) large; small

C) small;  small

D) small; large

E) none of the above

An element belonging to the alkaline earth family would be expected to have a ________ ionization energy and a ________ electron affinity.

A) large; large

B) large; small

C) small; small

D) small; large

E) none of the above

The term which best describes the crystalline substance that results when a large number of metal atoms transfers electrons to a large number of non-metal atoms is

A) covalent compound.

B) molecule.

C) ionic solid.

D) cation.

E) anion.

Which one of the compounds below is most likely to be ionic?

A) SrBr2        

B) NO2          

C) CBr4

D) H2O

 Which of the following pairs will form ionic bonds with one another?

A) N, C

B) Na, Ca

C) Cs, Br

D) S, Cl

Which of the following electron configurations is most stable?

A) 1s2 2s2

B) 1s2 2s2 2p2

C) 1s2 2s2 2p3

D) 1s2 2s2 2p4

E) 1s2 2s2 2p6

What is the most likely charge on an ion formed by an element with a valence electron configuration of ns2np4?

A) 2-

B) 1-

C) 2+

D) 4+

E) 6+

An atom with 3 valence electrons will most likely

A) lose three electrons.

B) gain three electrons.

C) gain five electrons.

D) gain one electron.

E) lose one electron.

Which element will form an ion with the greatest positive charge?

A) Al

B) Na

C) Mg

D) Sr

E) P

 The charge on a sulfide ion is ________.

A) 3+

B) 2+

C) 0

D) 2-

E) 3-

Which pair of elements is most likely to form an ionic compound if allowed to react together?

A) Al and Si

B) Fe and Ca

C) C and F

D) K and Br

E) H and N

 What fourth period element is represented by the dot structure shown?       X:

A) K

B) Ca

C) V

D) As

E) Ti

What fourth period element is represented by the dot structure shown?      _[image] 

A) K

B) Ca

C) Mn

D) Br

E) Co

Which of the following elements is most likely to form an ion with a -2 charge?

A) Mg

B) Si

C) S

D) K

E) Ti

The name of Cl- is

A) chlorine ion.

B) chloride ion.

C) chlorate ion.

D) chlorite ion.

E) diatomic chlorine.

The name of S2- is

A) sulfur.

B) sulfate ion.

C) sulfite ion.

D) sulfide ion.

E) sulfurous ion.

The name of Cu2+ is ________ ion or ________ ion.

A) copper; cupric

B) copper(i); cupric

C) copper(II); cupric

D) copper(I); cuprous

E) copper(II); cuprous

The correct Roman numeral for the chromium ion in the compound CrCl3 is

A) I

B) II

C) III

D) IV

The name of Sn2+ is ________ ion or ________ ion.

A) tin; stannous

B) tin(IV); stannic

C) tin(II); stannic

D) tin(IV); stannous

E) tin(II); stannous

Which of the following formulas in incorrect for a cobalt(III) compound?

A) CoCO3     

B) CoCl3

C) Co2O3

D) CoPO4  

 What is the formula of the ammonium ion?

A) Am-

B) Am+

C) ) [NH₄]+

D) [NH]4+

What is the formula of the carbonate ion?

A) [CO₂]3-

B) [CO₃]2-

C) [C₂O₄]2-

D) [C₂O₄]1-

The formula PO4 3- means that this ion is composed of

A) one atom of phosphorus, one atom of oxygen, and three extra electrons.

B) four atoms of phosphorus, four atoms or oxygen, and three extra electrons.

C) one atom of phosphorus,four atoms of oxygen, and three electrons have been lost.

D) one atom of phosphorus, four atoms of oxygen, and three extra electrons.

E) four atoms of phosphorus, four atoms of oxygen, and three electrons have been lost.

The permanganate ion is composed of

A) one atom of magnesium, four atoms of oxygen, and one extra electron.

B) one atom of manganese, four atoms of oxygen, and one extra electron.

C) four atoms of magnesium, four atoms of oxygen, and one extra electron.

D) four atoms of manganese, four atoms of oxygen, and one extra electron.

E) one manganese(II) ion, four oxide ions, and two extra electrons.

Which is the correct formula for the ionic compound containing iron(III) ions and oxide ions?

A) FeO

B) FeO2

C) Fe2O2

D) Fe2O3

E) Fe3O2

What is the formula for the ionic compound formed between calcium and sulfur?

A) CaS

B) CaSi

C) Ca2S

D) CaS2

E) CaSi2

What is the formula of a compound formed by the ions M2+ and X3-?

A) M2X3

B) M3X2

C) MX3

D) M2X

E) none of the above

What is the formula of a compound formed by the ions M+ and X3-?

A) MX3

B) M3X

C) M3X3

D) M2X6

E) none of the above

If an element G could react with sulfur to form an ionic compound with formula GS2, the charge on the ion formed by G would be ________.

A) 4-

B) 2-

C) 1+

D) 2+

E) 4+

 A formula unit of the ionic compound copper(II) carbonate consists of ________ copper(II) ions and ________ carbonate ions.

A) one; one

B) one; two

C) two; one

D) two; two

E) some other combination of ions

A formula unit of ammonium sulfate consists of ________ ammonium ions and ________ sulfate ions.

A) one; two

B) two; one

C) two; three

D) three; two

E) four; four

The formula Ca(NO3)2 tells us that one formula unit of this compound is composed of ________ calcium atoms, ________ nitrogen atoms, and ________ oxygen atoms.

A) one; two; six

B) two; two; six

C) one; two; five

D) one; one; five

E) one; one; six

The formula for the compound chromium(II) nitrate is ________.

A) C2NO3

B) Cr2NO3

C) CrNO3

D) Cr(NO3)2

E) CrNO2

What is the name of Mg3(PO4)2?

A) trimagnesium diphosphate

B) magnesium diphosphate

C) trimagnesium phosphate

D) magnesium phosphate

E) magnesium phosphorus oxide

What is the name of AlCl3?

A) aluminum chloride

B) aluminum(III) chloride

C) aluminum carbide

D) aluminum trichloride

E) aluminum tricarbide

The formula for ammonium hydroxide is ________.

A) OHNH4

B) NH4NO3

C) NH4O

D) NH4OH

E) Al(OH)3

Which of the following formulas represents a compound that is a base?

A) CaSO4

B) NH4Cl

C) Mg(OH)2

D) H2

E) none of the above

One definition of an acid is a substance that provides which ion in water solution?

A) Na+

B) H+

C) OH-

D) NH4+

E) none of the above

One definition of a base is a substance that provides which ion in water solution?

A) Na+

B) H+

C) OH-

D) NH4+

E) none of the above

Significant figures

Rules:

1. Zeros in the middle of of a number are like any other digits; they are  ALWAYS significant.

2. Zeros at the beginning of a number are NOT significant; they act only to locate a decimal point

3. Zeros at the end of a number and after the decimal point AREsignificant. It is assumed that these zeros would not be shown unless they are significant.

4. Zeros at the end of a number and before an implied decimal point may or may not be significant.

Number of protons and electrons 

30

Z

30

Zn

65.4

Number of protons and neurons

65.4 - 30 = 35.4

Zn= 1s2 2s2 2p6 3s2 3p6 4s2 3d10

 1.0 cal /  g°  C

Δt= Q/mC

C = Q / m Δt

(cal / g° C)

= 300 cal / (50.0g)(1.0cal / g°C)

= 6.00 °C

Q = energy

m = mass

C = specific heat

Δt = change in temperature

Q=mCΔt

Kilo (K) = 1000   10³

base = 1

centi (c) = 1/100 =10^-2

mili (m) = 1/1000 = 10^-3

micro (µ) = 1/1 000 000 = 10^-6

nano (n) = 1/1 000 000 000 =10^-9

D = m/v

V = m/d

M = vd

CO_3^-2     Carbonate ; stays CO_3^-2 

SO_4^-2          Sulfate

PO_4^-3  Phosphate

OH ^-    Hydroxide

NH₄    Ammonia   

NO₃    Nitrate

Hypothetical!!

What is the average mass of Fluorine if it exists at 

• 80% F 18.96
• 10% F 19.02
• 8%   F 19.53
• 2%   F 18.10

Σ (0.80 x 18.96) + (0.10 x 19.02) + (0.08 x 19.53) + (0.02 x 18.10) =

     18.9944