What parts make up What parts make up an atom?an atom?

Coach ScruggsCoach Scruggs

88thth Grade Grade

What makes up an atom?What makes up an atom?

It is hard to believe how It is hard to believe how tiny an atom is. Yet, the tiny an atom is. Yet, the tiny atom is made up of tiny atom is made up of even even smallersmaller parts. parts. Can you imagine how Can you imagine how small these parts are?small these parts are?

An atom has 3 main An atom has 3 main parts: protons, parts: protons, neutrons, and neutrons, and electrons.electrons.

► ProtonsProtons and and neutronsneutrons make up the center of make up the center of an atom. The center an atom. The center part of an atom is part of an atom is called the called the nucleusnucleus..

► The The electronselectrons are are outside the nucleus. outside the nucleus. They spin around the They spin around the nucleus at very great nucleus at very great speeds. Electrons are speeds. Electrons are much smaller than much smaller than protons and neutrons.protons and neutrons.

Parts of an AtomParts of an Atom

► NucleusNucleus: the center : the center part of an atompart of an atom

► ProtonProton: found inside : found inside the nucleus; a proton the nucleus; a proton has a plus (+) electrical has a plus (+) electrical chargecharge

► NeutronNeutron: found inside : found inside the nucleus; a neutron the nucleus; a neutron has no electrical chargehas no electrical charge

► ElectronElectron: moves : moves around the nucleus; an around the nucleus; an electron has a minus (-) electron has a minus (-) electrical chargeelectrical charge

Protons and electrons have electrical Protons and electrons have electrical charges.charges.

►Each proton has a positive (+) Each proton has a positive (+) charge.charge.

►Each electron has a negative (-) Each electron has a negative (-) charge.charge.

A neutron is neutral. It has no charge.A neutron is neutral. It has no charge.

An atom has the same number of An atom has the same number of protons as electrons.protons as electrons.

PROTONS (+) = ELECTRONS PROTONS (+) = ELECTRONS (-)(-)

This means that the number of plus (+) This means that the number of plus (+) charges equals (=) the number of charges equals (=) the number of minus (-) charges. They balance each minus (-) charges. They balance each other. other. Because of this, the entire atom Because of this, the entire atom has no charge.has no charge.

PROTONS (+) = ATOMIC PROTONS (+) = ATOMIC NUMBERNUMBER

The atomic number is also the same as the The atomic number is also the same as the number of protons.number of protons.

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These three things are equal:These three things are equal:

PP rotons = rotons = EE lectrons = lectrons = NN umber (atomic) umber (atomic)

If you know any of these numbers, you know If you know any of these numbers, you know the number of the other two. the number of the other two. They are the They are the same!same!

Answer these questions.Answer these questions.1.1. Name the parts that make up a nucleus.Name the parts that make up a nucleus.2.2. A proton is ____larger___ (larger, smaller) than A proton is ____larger___ (larger, smaller) than

an electron.an electron.3.3. An electron is ______smaller (larger, smaller) An electron is ______smaller (larger, smaller)

than a neutron.than a neutron.4.4. A proton has _____positive__ (a positive, a A proton has _____positive__ (a positive, a

negative, no) charge.negative, no) charge.5.5. An electron has ____negative___ (a positive, a An electron has ____negative___ (a positive, a

negative, no) charge.negative, no) charge.6.6. A neutron has __no____ (a positive, a A neutron has __no____ (a positive, a

negative, no) charge.negative, no) charge.7.7. An entire atom has _____positive___ (a An entire atom has _____positive___ (a

positive, a negative, no) charge.positive, a negative, no) charge.

Name of Name of ElementElement

SymbolSymbol Atomic NumberAtomic Number Number of Number of ProtonsProtons

Number of Number of ElectronsElectrons

1.1. OxygenOxygen OO 88 88 88

2.2. CalciumCalcium CaCa 2020 2020 2020

3.3. IodineIodine II 5353 5353 5353

4.4. NalgoenNalgoen NaNa 1111 1111 1111

5.5. SilverSilver AgAg 4747 4747 4747

6.6. SulfurSulfurS

1616 1616 1616

7.7. MercuryMercury HgHg 8080 8080 8080

8.8. IronIron FeFe 2626 2626 2626

You will need your Periodic Table to fill in some spaces.

ATOMIC WEIGHTATOMIC WEIGHT

The The weight of an atomweight of an atom is is the the weight of its weight of its nucleusnucleus. A nucleus . A nucleus contains protons and contains protons and neutrons. Therefore, the neutrons. Therefore, the number of number of protonsprotons plus plus the number of the number of neutronsneutrons gives us the gives us the atomic atomic weightweight of an atom. of an atom. Electrons are so light, Electrons are so light, that they are not that they are not counted in the atomic counted in the atomic weight.weight.

Every atom has weight. Every atom has weight. The weight of an atom The weight of an atom is called its is called its atomic atomic weightweight. An atomic . An atomic weight is not an exact weight is not an exact scale reading of weight scale reading of weight – like grams or ounces. – like grams or ounces. It is a way of comparing It is a way of comparing the weight of one atom the weight of one atom against the weight of against the weight of another atom.another atom.

ATOMIC WEIGHTATOMIC WEIGHT

► Each proton is given Each proton is given a weight of a weight of ONEONE..

► Each neutron is Each neutron is given a weight of given a weight of ONEONE..

► Each different kind Each different kind of atom has its own of atom has its own number of protons.number of protons.

► Each different kind Each different kind of atom has its own of atom has its own atomic number.atomic number.

ATOMIC WEIGHT for LithiumATOMIC WEIGHT for Lithium

Example:Example:

A lithium atom has 3 A lithium atom has 3 protons and 4 protons and 4 neutrons. The neutrons. The atomic weight is 7 atomic weight is 7 (3 + 4 = 7)(3 + 4 = 7)

Answer these questions.Answer these questions.

1.1. What is the center part of the atom? What is the center part of the atom?

NucleusNucleus

2.2. What parts make up the nucleus? What parts make up the nucleus?

Protons and Neutrons Protons and Neutrons

3.3. The weight of an atom is the weight of The weight of an atom is the weight of

its ___Protons____ and ___Neutrons___.its ___Protons____ and ___Neutrons___.

4.4. Fill in the blanks.Fill in the blanks.

ATOMIC WEIGHT=Protons_+Neutrons____ATOMIC WEIGHT=Protons_+Neutrons____

Name of ElementName of Element SymbolSymbol Number of Number of ProtonsProtons

Number of Number of NeutronsNeutrons

Atomic WeightAtomic Weight

5.5. NeonNeon NeNe 1010 1010 2020

6.6. CobaltCobalt CoCo 2727 3232 5959

7.7. GoldGold AuAu 7979 118118 197197

8.8. ChlorineChlorine ClCl 1717 1818 3535

9.9. ThoriumThorium ThTh 9090 142142 232232

10.10. LeadLead PbPb 8282 125125 207207

11.11. NickelNickel NiNi 2828 3131 5959

12.12. ChromiumChromium CrCr 2424 2828 5252

13.13. SiliconSilicon SiSi 1414 1414 2828

14.14. TungstenTungsten WW 7474 110110 184184

Now fill in the chart.

ROUNDING Atomic WeightsROUNDING Atomic Weights

►Atomic weights are not written as whole Atomic weights are not written as whole numbers. They are written as decimals.numbers. They are written as decimals.

Example: Copper 63.54Example: Copper 63.54►We round off the decimal to its nearest We round off the decimal to its nearest

whole number. If the decimal is .5 or whole number. If the decimal is .5 or greater we round to the next higher greater we round to the next higher number. If the decimal is less than .5 we number. If the decimal is less than .5 we round down.round down.

Example: Copper 64Example: Copper 64

ElementElement Listed Atomic WeightListed Atomic Weight Rounded-Off Atomic Rounded-Off Atomic WeightWeight

1.1. CopperCopper 63.5463.54 6464

2.2. CalciumCalcium 40.0840.08 4040

3.3. FluorineFluorine 18.9918.99 1919

4.4. StrontiumStrontium 87.6287.62 8888

5.5. BariumBarium 137.34137.34 137137

6.6. TitaniumTitanium 47.9047.90 4848

7.7. MagnesiumMagnesium 24.3124.31 2424

8.8. ArgonArgon 39.9439.94 4040

9.9. ErbiumErbium 167.26167.26 167167

10.10. ZirconiumZirconium 91.2291.22 9191

Use this knowledge to fill in the chart. The first two are done as examples.

What do the pictures show?What do the pictures show?Figures D and E show atoms. Study each figure and Figures D and E show atoms. Study each figure and

answer the questions about each.answer the questions about each.

1.1. How many protons How many protons does the atom in does the atom in Figure E have? 2Figure E have? 2

2.2. How many neutrons? 2How many neutrons? 2

3.3. How many electrons? How many electrons? 22

4.4. What is the atomic What is the atomic weight of this atom? 4weight of this atom? 4

5.5. What is the name and What is the name and symbol of this atom?symbol of this atom?

Name Helium______Name Helium______

Symbol __He__________Symbol __He__________

Figure E

What do the pictures show?What do the pictures show?Figures D and E show atoms. Study each figure and Figures D and E show atoms. Study each figure and

answer the questions about each.answer the questions about each.

1.1. How many protons does How many protons does the atom in Figure D the atom in Figure D have? 9have? 9

2.2. How many neutrons? How many neutrons? 1010

3.3. How many electrons? 9How many electrons? 9

4.4. What is the atomic What is the atomic weight of this atom? 19weight of this atom? 19

5.5. What is the name and What is the name and symbol of this atom?symbol of this atom?

Name ___Neon______Name ___Neon______

Symbol Ne______Symbol Ne______

Figure D

Completing SentencesCompleting SentencesComplete the sentences with the choices below. Two Complete the sentences with the choices below. Two

of these may be used twice. Two of these may be of these may be used twice. Two of these may be used three times.used three times.

WORD BOXWORD BOX

plusplusnononeutronsneutronsatomic numberatomic numberatomsatoms11circlecircleelectronselectronsminusminusprotonsprotons

1.1. All matter is made up of All matter is made up of tiny __atoms____.tiny __atoms____.

2.2. The three main parts of The three main parts of an atom are an atom are protons____, protons____, _____neutrons__, and _____neutrons__, and ____electrons____.____electrons____.

3.3. A nucleus is made up of A nucleus is made up of ___proton___ and ___proton___ and _____neutron__._____neutron__.

4.4. Electrons __minus__ the Electrons __minus__ the nucleus.nucleus.

5.5. A proton has a A proton has a __positive__ charge; an __positive__ charge; an electron has a _negative electron has a _negative charge; and a neutron charge; and a neutron has a _no_ charge.has a _no_ charge.

Completing SentencesCompleting SentencesComplete the sentences with the choices below. Two Complete the sentences with the choices below. Two

of these may be used twice. Two of these may be of these may be used twice. Two of these may be used three times.used three times.

WORD BOXWORD BOX

plusplusnononeutronsneutronsatomic numberatomic numberatomsatoms11circlecircleelectronselectronsminusminusprotonsprotons

1.1. An entire atom has An entire atom has ___no__ charge.___no__ charge.

2.2. Protons = electrons = Protons = electrons = ___neutrons_____neutrons__

3.3. The atomic weight of The atomic weight of an atom is the weight an atom is the weight of its __circle__ and of its __circle__ and _atoms__._atoms__.

4.4. Each proton or neutron Each proton or neutron is give a weight of is give a weight of __1___.__1___.

5.5. In figuring atomic In figuring atomic weight, we do not weight, we do not count the weight of an count the weight of an atom’s __number___.atom’s __number___.

MatchingMatchingMatch the two lists. Write the correct letter on the Match the two lists. Write the correct letter on the

line next to each number.line next to each number.

1.1. _c_ protons and neutrons_c_ protons and neutrons a. no chargea. no charge

2.2. _e_ electron_e_ electron b. add an b. add an atom’s atom’s protons and protons and

neutrons neutrons

3.3. _d_ proton_d_ proton c. make up a c. make up a nucleusnucleus

4.4. _a_ neutron_a_ neutron d. positive charged. positive charge

5.5. _b_ to find atomic weight_b_ to find atomic weight e. negative e. negative chargecharge