![Page 1: Atoms, Isotopes and Ions An atom consists of a nucleusnucleus –(of protons and neutrons) electrons in space about the nucleus.electrons in space about](https://reader033.vdocuments.net/reader033/viewer/2022061305/55144c91550346494e8b4ef3/html5/thumbnails/1.jpg)
Atoms, Isotopes and Ions
![Page 2: Atoms, Isotopes and Ions An atom consists of a nucleusnucleus –(of protons and neutrons) electrons in space about the nucleus.electrons in space about](https://reader033.vdocuments.net/reader033/viewer/2022061305/55144c91550346494e8b4ef3/html5/thumbnails/2.jpg)
An atom consists of aAn atom consists of a
• nucleusnucleus
– (of (of protonsprotons and and neutronsneutrons) )
• electronselectrons in space about the nucleus. in space about the nucleus.
The The AtomAtom
NucleusNucleus
Electron cloudElectron cloud
![Page 3: Atoms, Isotopes and Ions An atom consists of a nucleusnucleus –(of protons and neutrons) electrons in space about the nucleus.electrons in space about](https://reader033.vdocuments.net/reader033/viewer/2022061305/55144c91550346494e8b4ef3/html5/thumbnails/3.jpg)
Copper Copper atoms on atoms on silica silica surface.surface.
• An An __________ is the smallest particle of is the smallest particle of an element that has the chemical an element that has the chemical properties of the element.properties of the element.
Distance across = 1.8 nanometer (1.8 x 10-9 m)
![Page 4: Atoms, Isotopes and Ions An atom consists of a nucleusnucleus –(of protons and neutrons) electrons in space about the nucleus.electrons in space about](https://reader033.vdocuments.net/reader033/viewer/2022061305/55144c91550346494e8b4ef3/html5/thumbnails/4.jpg)
AA MOLECULEMOLECULE is the smallest unit of is the smallest unit of a compound that retains the chemical a compound that retains the chemical characteristics of the compound.characteristics of the compound.
Composition of molecules is given by aComposition of molecules is given by a
MOLECULAR FORMULAMOLECULAR FORMULA
HH22OO CC88HH1010NN44OO22 - caffeine - caffeine
![Page 5: Atoms, Isotopes and Ions An atom consists of a nucleusnucleus –(of protons and neutrons) electrons in space about the nucleus.electrons in space about](https://reader033.vdocuments.net/reader033/viewer/2022061305/55144c91550346494e8b4ef3/html5/thumbnails/5.jpg)
Dalton’s Atomic Theory
John Dalton (1766-1844) proposed an atomic theory
While this theory was not completely correct, it revolutionized how chemists looked at matter and brought about chemistry as we know it today instead of alchemy
Thus, it’s an important landmark in the history of science.
![Page 6: Atoms, Isotopes and Ions An atom consists of a nucleusnucleus –(of protons and neutrons) electrons in space about the nucleus.electrons in space about](https://reader033.vdocuments.net/reader033/viewer/2022061305/55144c91550346494e8b4ef3/html5/thumbnails/6.jpg)
Dalton’s Atomic Theory - Summary
1. matter is composed, indivisible particles (atoms)2. all atoms of a particular element are identical3. different elements have different atoms4. atoms combine in certain whole-number ratios 5. In a chemical reaction, atoms are merely
rearranged to form new compounds; they are not created, destroyed, or changed into atoms of any other elements.
![Page 7: Atoms, Isotopes and Ions An atom consists of a nucleusnucleus –(of protons and neutrons) electrons in space about the nucleus.electrons in space about](https://reader033.vdocuments.net/reader033/viewer/2022061305/55144c91550346494e8b4ef3/html5/thumbnails/7.jpg)
Problems with Dalton’s Atomic Theory?1. matter is composed, indivisible particles
Atoms Can Be Divided, but only in a nuclear reaction2. all atoms of a particular element are identical
Does Not Account for Isotopes (atoms of the same element but a different mass due to a different number of neutrons)!
3. different elements have different atomsYES!
4. atoms combine in certain whole-number ratiosYES! Called the Law of Definite Proportions
5. In a chemical reaction, atoms are merely rearranged to form new compounds; they are not created, destroyed, or changed into atoms of any other elements.Yes, except for nuclear reactions that can change atoms of one element to a different element
![Page 8: Atoms, Isotopes and Ions An atom consists of a nucleusnucleus –(of protons and neutrons) electrons in space about the nucleus.electrons in space about](https://reader033.vdocuments.net/reader033/viewer/2022061305/55144c91550346494e8b4ef3/html5/thumbnails/8.jpg)
ATOM ATOM COMPOSITIONCOMPOSITION
•protons and neutrons in protons and neutrons in the nucleus.the nucleus.
•the number of electrons is equal to the the number of electrons is equal to the number of protons.number of protons.
•electrons in space around the nucleus.electrons in space around the nucleus.
•extremely small. One teaspoon of water has extremely small. One teaspoon of water has 3 times as many atoms as the Atlantic Ocean 3 times as many atoms as the Atlantic Ocean has teaspoons of water.has teaspoons of water.
The atom is mostlyThe atom is mostlyempty spaceempty space
![Page 9: Atoms, Isotopes and Ions An atom consists of a nucleusnucleus –(of protons and neutrons) electrons in space about the nucleus.electrons in space about](https://reader033.vdocuments.net/reader033/viewer/2022061305/55144c91550346494e8b4ef3/html5/thumbnails/9.jpg)
ATOMIC COMPOSITIONATOMIC COMPOSITION• Protons (pProtons (p++))
– + electrical charge+ electrical charge
– mass = 1.672623 x 10mass = 1.672623 x 10-24-24 g g
– relative mass = 1.007 atomic relative mass = 1.007 atomic mass units mass units (amu) (amu) but we can round to 1but we can round to 1
• Electrons (eElectrons (e--))– negative electrical chargenegative electrical charge
– relative mass = 0.0005 amu relative mass = 0.0005 amu but we can round to 0but we can round to 0
• Neutrons (nNeutrons (noo))– no electrical chargeno electrical charge
– mass = 1.009 amu mass = 1.009 amu but we can round to 1but we can round to 1
![Page 10: Atoms, Isotopes and Ions An atom consists of a nucleusnucleus –(of protons and neutrons) electrons in space about the nucleus.electrons in space about](https://reader033.vdocuments.net/reader033/viewer/2022061305/55144c91550346494e8b4ef3/html5/thumbnails/10.jpg)
Atomic Number, ZAtomic Number, Z
All atoms of the same element All atoms of the same element have the same number of have the same number of protons in the nucleus, protons in the nucleus, ZZ
1313
AlAl
26.98126.981
Atomic numberAtomic number
Atom symbolAtom symbol
AVERAGE Atomic MassAVERAGE Atomic Mass
![Page 11: Atoms, Isotopes and Ions An atom consists of a nucleusnucleus –(of protons and neutrons) electrons in space about the nucleus.electrons in space about](https://reader033.vdocuments.net/reader033/viewer/2022061305/55144c91550346494e8b4ef3/html5/thumbnails/11.jpg)
Mass Number, AMass Number, A• C atom with 6 protons and 6 neutrons C atom with 6 protons and 6 neutrons
is the mass standard is the mass standard • = 12 atomic mass units= 12 atomic mass units• Mass NumberMass Number (A) (A)
= # protons + # neutrons= # protons + # neutrons• NOT on the periodic table…(it is the NOT on the periodic table…(it is the
AVERAGE atomic mass on the table)AVERAGE atomic mass on the table)• A boron atom can have A boron atom can have
A = 5 p + 5 n = 10 amuA = 5 p + 5 n = 10 amu
A
Z
10
5B
A
Z
10
5B
![Page 12: Atoms, Isotopes and Ions An atom consists of a nucleusnucleus –(of protons and neutrons) electrons in space about the nucleus.electrons in space about](https://reader033.vdocuments.net/reader033/viewer/2022061305/55144c91550346494e8b4ef3/html5/thumbnails/12.jpg)
IsotopesIsotopes• Atoms of the same element that have Atoms of the same element that have
the same atomic number but different the same atomic number but different atomic masses due to a different atomic masses due to a different number of neutronsnumber of neutrons
• Boron-10 (Boron-10 (1010B) has 5 p and 5 nB) has 5 p and 5 n
• Boron-11 (Boron-11 (1111B) has 5 p and 6 nB) has 5 p and 6 n
10B
11B
![Page 13: Atoms, Isotopes and Ions An atom consists of a nucleusnucleus –(of protons and neutrons) electrons in space about the nucleus.electrons in space about](https://reader033.vdocuments.net/reader033/viewer/2022061305/55144c91550346494e8b4ef3/html5/thumbnails/13.jpg)
Figure 3.10: Two isotopes of sodium.
![Page 14: Atoms, Isotopes and Ions An atom consists of a nucleusnucleus –(of protons and neutrons) electrons in space about the nucleus.electrons in space about](https://reader033.vdocuments.net/reader033/viewer/2022061305/55144c91550346494e8b4ef3/html5/thumbnails/14.jpg)
Isotopes Isotopes & Their & Their
UsesUsesBone scans with Bone scans with radioactive radioactive technetium-99. technetium-99.
![Page 15: Atoms, Isotopes and Ions An atom consists of a nucleusnucleus –(of protons and neutrons) electrons in space about the nucleus.electrons in space about](https://reader033.vdocuments.net/reader033/viewer/2022061305/55144c91550346494e8b4ef3/html5/thumbnails/15.jpg)
Isotopes & Their Isotopes & Their UsesUses
The The tritiumtritium content of ground water is content of ground water is used to discover the source of the water, used to discover the source of the water, for example, in municipal water or the for example, in municipal water or the source of the steam from a volcano. source of the steam from a volcano.
![Page 16: Atoms, Isotopes and Ions An atom consists of a nucleusnucleus –(of protons and neutrons) electrons in space about the nucleus.electrons in space about](https://reader033.vdocuments.net/reader033/viewer/2022061305/55144c91550346494e8b4ef3/html5/thumbnails/16.jpg)
Atomic Symbols
Show the name of the element, a hyphen, and
the mass number in hyphen notation
sodium-23
Show the mass number and atomic number
in nuclear symbol formmass number 23 Na
atomic number 11
![Page 17: Atoms, Isotopes and Ions An atom consists of a nucleusnucleus –(of protons and neutrons) electrons in space about the nucleus.electrons in space about](https://reader033.vdocuments.net/reader033/viewer/2022061305/55144c91550346494e8b4ef3/html5/thumbnails/17.jpg)
Isotopes?
Which of the following represent isotopes of the same element? Which element?
234 X 234
X235
X238
X
92 93 92 92
![Page 18: Atoms, Isotopes and Ions An atom consists of a nucleusnucleus –(of protons and neutrons) electrons in space about the nucleus.electrons in space about](https://reader033.vdocuments.net/reader033/viewer/2022061305/55144c91550346494e8b4ef3/html5/thumbnails/18.jpg)
Counting Protons, Neutrons, and Electrons
• Protons: Atomic Number (from periodic table)• Neutrons: Mass Number minus the number of protons
(mass number is protons and neutrons because the mass of electrons is negligible)
• Electrons: – If it’s an atom, the protons and electrons must be
the SAME so that it is has a net charge of zero (equal numbers of + and -)
– If it does NOT have an equal number of electrons, it is not an atom, it is an ION. For each negative charge, add an extra electron. For each positive charge, subtract an electron (Don’t add a proton!!! That changes the element!)
![Page 19: Atoms, Isotopes and Ions An atom consists of a nucleusnucleus –(of protons and neutrons) electrons in space about the nucleus.electrons in space about](https://reader033.vdocuments.net/reader033/viewer/2022061305/55144c91550346494e8b4ef3/html5/thumbnails/19.jpg)
Learning Check – Counting
Naturally occurring carbon consists of three isotopes, 12C, 13C, and 14C. State the number of protons, neutrons, and electrons in each of these carbon atoms.
12C 13C 14C 6 6 6
#p+ _______ _______ _______
#no _______ _______ _______
#e- _______ _______ _______
![Page 20: Atoms, Isotopes and Ions An atom consists of a nucleusnucleus –(of protons and neutrons) electrons in space about the nucleus.electrons in space about](https://reader033.vdocuments.net/reader033/viewer/2022061305/55144c91550346494e8b4ef3/html5/thumbnails/20.jpg)
Answers
12C 13C 14C 6 6 6
#p+ 6 6 6
#no 6 7 8
#e- 6 6 6
![Page 21: Atoms, Isotopes and Ions An atom consists of a nucleusnucleus –(of protons and neutrons) electrons in space about the nucleus.electrons in space about](https://reader033.vdocuments.net/reader033/viewer/2022061305/55144c91550346494e8b4ef3/html5/thumbnails/21.jpg)
Learning Check
An atom has 14 protons and 20 neutrons.A. Its atomic number is
1) 14 2) 16 3) 34
B. Its mass number is1) 14 2) 16 3) 34
C. The element is1) Si 2) Ca 3) Se
D. Another isotope of this element is
1) 34X 2) 34X 3) 36X 16 14 14
![Page 22: Atoms, Isotopes and Ions An atom consists of a nucleusnucleus –(of protons and neutrons) electrons in space about the nucleus.electrons in space about](https://reader033.vdocuments.net/reader033/viewer/2022061305/55144c91550346494e8b4ef3/html5/thumbnails/22.jpg)
IONS IONS
• IONSIONS are atoms or groups of atoms with a positive or negative are atoms or groups of atoms with a positive or negative
charge. charge.
• Taking awayTaking away an electron from an atom gives a an electron from an atom gives a CATIONCATION with a with a
positive chargepositive charge
• AddingAdding an electron to an atom gives an an electron to an atom gives an ANIONANION with a with a
negative chargenegative charge..
• To tell the difference between an atom and an ion, look to see if To tell the difference between an atom and an ion, look to see if
there is a charge in the superscript! Examples: Nathere is a charge in the superscript! Examples: Na++ Ca Ca+2+2 I I-- O O-2-2
Na Ca I ONa Ca I O
![Page 23: Atoms, Isotopes and Ions An atom consists of a nucleusnucleus –(of protons and neutrons) electrons in space about the nucleus.electrons in space about](https://reader033.vdocuments.net/reader033/viewer/2022061305/55144c91550346494e8b4ef3/html5/thumbnails/23.jpg)
Forming Cations & Forming Cations & AnionsAnions
Forming Cations & Forming Cations & AnionsAnions
A A CATIONCATION forms forms when an when an atom atom losesloses one or one or more electrons.more electrons.
An An ANIONANION forms forms when an when an atom atom gainsgains one or one or more electronsmore electrons
Mg --> Mg2+ + 2 e- F + e- --> F-
![Page 24: Atoms, Isotopes and Ions An atom consists of a nucleusnucleus –(of protons and neutrons) electrons in space about the nucleus.electrons in space about](https://reader033.vdocuments.net/reader033/viewer/2022061305/55144c91550346494e8b4ef3/html5/thumbnails/24.jpg)
PREDICTING ION CHARGESPREDICTING ION CHARGESPREDICTING ION CHARGESPREDICTING ION CHARGES
In generalIn general
• metalsmetals (Mg) (Mg) lose electrons lose electrons ---> ---> cationscations
• nonmetalsnonmetals (F) (F) gain electronsgain electrons ---> ---> anionsanions
![Page 25: Atoms, Isotopes and Ions An atom consists of a nucleusnucleus –(of protons and neutrons) electrons in space about the nucleus.electrons in space about](https://reader033.vdocuments.net/reader033/viewer/2022061305/55144c91550346494e8b4ef3/html5/thumbnails/25.jpg)
Learning Check – Counting
State the number of protons, neutrons, and electrons in each of these ions.
39 K+ 16O -2 41Ca +2
19 8 20
#p+ ______ ______ _______
#no ______ ______ _______
#e- ______ ______ _______
![Page 26: Atoms, Isotopes and Ions An atom consists of a nucleusnucleus –(of protons and neutrons) electrons in space about the nucleus.electrons in space about](https://reader033.vdocuments.net/reader033/viewer/2022061305/55144c91550346494e8b4ef3/html5/thumbnails/26.jpg)
One Last Learning Check
Write the nuclear symbol form for the following atoms or ions:
A. 8 p+, 8 n, 8 e- ___________
B. 17p+, 20n, 17e- ___________
C. 47p+, 60 n, 46 e- ___________
![Page 27: Atoms, Isotopes and Ions An atom consists of a nucleusnucleus –(of protons and neutrons) electrons in space about the nucleus.electrons in space about](https://reader033.vdocuments.net/reader033/viewer/2022061305/55144c91550346494e8b4ef3/html5/thumbnails/27.jpg)
AVERAGE AVERAGE ATOMIC ATOMIC MASSMASS
• Because of the existence of isotopes, the Because of the existence of isotopes, the mass of a collection of atoms has an average mass of a collection of atoms has an average value.value.
• Boron is 20% Boron is 20% 1010B and 80% B and 80% 1111B. That is, B. That is, 1111B is B is 80 percent abundant on earth. 80 percent abundant on earth.
• For boron atomic weightFor boron atomic weight
= 0.20 (10 amu) + 0.80 (11 amu) = 10.8 amu= 0.20 (10 amu) + 0.80 (11 amu) = 10.8 amu
10B
11B
![Page 28: Atoms, Isotopes and Ions An atom consists of a nucleusnucleus –(of protons and neutrons) electrons in space about the nucleus.electrons in space about](https://reader033.vdocuments.net/reader033/viewer/2022061305/55144c91550346494e8b4ef3/html5/thumbnails/28.jpg)
Isotopes & Average Atomic Isotopes & Average Atomic MassMass
• Because of the existence of isotopes, the mass Because of the existence of isotopes, the mass of a collection of atoms has an average value.of a collection of atoms has an average value.
• 66Li = 7.5% abundant and Li = 7.5% abundant and 77Li = 92.5%Li = 92.5%
–Avg. Atomic mass of Li = ______________Avg. Atomic mass of Li = ______________
• 2828Si = 92.23%, Si = 92.23%, 2929Si = 4.67%, Si = 4.67%, 3030Si = 3.10%Si = 3.10%
–Avg. Atomic mass of Si = ______________Avg. Atomic mass of Si = ______________
![Page 29: Atoms, Isotopes and Ions An atom consists of a nucleusnucleus –(of protons and neutrons) electrons in space about the nucleus.electrons in space about](https://reader033.vdocuments.net/reader033/viewer/2022061305/55144c91550346494e8b4ef3/html5/thumbnails/29.jpg)
Rutherford’s experiment.
![Page 30: Atoms, Isotopes and Ions An atom consists of a nucleusnucleus –(of protons and neutrons) electrons in space about the nucleus.electrons in space about](https://reader033.vdocuments.net/reader033/viewer/2022061305/55144c91550346494e8b4ef3/html5/thumbnails/30.jpg)
The modern view of the atom was developed The modern view of the atom was developed by by Ernest RutherfordErnest Rutherford (1871-1937). (1871-1937).
![Page 31: Atoms, Isotopes and Ions An atom consists of a nucleusnucleus –(of protons and neutrons) electrons in space about the nucleus.electrons in space about](https://reader033.vdocuments.net/reader033/viewer/2022061305/55144c91550346494e8b4ef3/html5/thumbnails/31.jpg)
Results of foil
experiment if Plum
Pudding model had
been correct.
![Page 32: Atoms, Isotopes and Ions An atom consists of a nucleusnucleus –(of protons and neutrons) electrons in space about the nucleus.electrons in space about](https://reader033.vdocuments.net/reader033/viewer/2022061305/55144c91550346494e8b4ef3/html5/thumbnails/32.jpg)
What Actually Happened