Chemical Foundations: Elements, Atoms, and Ions Adapted from

The Elements –Pure substances that cannot be broken apart by a chemical reaction –All elements are listed on the Periodic Table Sodium Bromine Aluminum

Elements and Symbols You are responsible for knowing the element names and symbols for the 44 elements listed on page _____ of your Chapter 1 Packet. Single letter symbols (ex. H, C, O) are always capitalized! Two letter symbols (ex. Fe, Ca, Zn) have the first letter capitalized and the second letter is lower case

Symbol Variations Symbol is the first letter of the name –Carbon (C), Boron (B), Nitrogen (N) Symbol is the first two letters of the name Calcium (Ca), Neon (Ne), Argon (Ar) Symbol is the first and third letter of the name –Magnesium (Mg), Manganese (Mn), Chlorine (Cl) Symbol is based on the Latin name –See chart on next slide

Elements with Symbols based on Latin Names English NameLatin NameSymbol AntimonyStibiumSb CopperCuprumCu GoldAurumAu IronFerrumFe LeadPlumbumPb MercuryHydrargyrumHg PotassiumKaliumK SilverArgentumAg SodiumNatriumNa TinStannumSn TungstenWolframW

LecturePLUS Timberlake6 Learning Check Select the correct symbol for each: A. Calcium 1) C2) Ca3) CA B. Sulfur 1) S2) Sl3) Su C. Iron 1) Ir2) FE3) Fe

LecturePLUS Timberlake7 Learning Check Select the correct name for each: A. N 1) neon2) nitrogen 3) nickel B.P 1) Potassium 2)phogiston 3) phosphorus C. Ag 1) silver2) agean3) gold

And now this… The NEW Periodic Table Video Meet the Elements

The Periodic Table Dmitri Mendeleev ( )

Periods in the Periodic Table Periods are the ROWS on the Periodic Table There are 7 rows on the Periodic Table H and He are in Row #1

Groups in the Periodic Table Columns on the Periodic Table are called Groups Elements in groups react in similar ways Main Group Elements are labeled with an “A” Transition Metals are labeled with a “B”

Group Names Red – Alkali Metals (1A) Orange – Alkaline Earth Metals (2A) Yellow – Boron Group (3A) Green – Carbon Group (4A) Sea Green – Nitrogen Group (5A) Light Blue – Oxygen Group (6A) Dark Blue – Halogens (7A) Purple – Noble Gases (8A) White - Transition Metals (Upper Middle Section) Inner Transition Metals (Lower 2 Rows)

LecturePLUS Timberlake13 Learning Check A. Element in Group 7A, period 4 1) Br2) Cl3) Mn B. Element in Group 2A, Period 3 1) beryllium2) magnesium 3) boron C. Metals in Group 4A 1) Ge, Sn, Pb 2) C, Si 3) C, Si, Ge, Sn D. Nonmetals in Group 5A 1) As, Sb, Bi 2) N, P, As 3) N, P, As, Sb

Metals, Non-Metals and Metalloids

Metals Good conductors of heat and electricity High Luster (Shiny) All solids (except Mercury) Malleable (can hammer into thin sheets/foils) and Ductile (can be pulled into wires)

Non-metals Non-conductors (Insulators) Dull Can be solids, liquids or gases Brittle

Metalloids Exhibit properties of both metals and non- metals Semi-Conductors –Conductors at high temperatures, insulators at low temperatures

LecturePLUS Timberlake18 Learning Check Specify metal (1) or nonmetal (2) for each: A. sulfur____ B. Chlorine____ C. sodium____ D. iron____ E. carbon____ F. silver____

LecturePLUS Timberlake 19 Learning Check Select the correct elements: A. Metals in Group 4A 1) Ge, Sn, Pb 2) C, Si 3) C, Si, Ge, Sn B. Nonmetals in Group 5A 1) As, Sb, Bi 2) N, P, As 3) N, P, As, Sb

An atom consists of a nucleusnucleus –(of protons and neutrons) electrons in space about the nucleus.electrons in space about the nucleus. The Atom Nucleus Electron cloud

Copper atoms on silica surface. An _____ is the smallest particle of an element that has the chemical properties of the element.An _____ is the smallest particle of an element that has the chemical properties of the element. Distance across = 1.8 nanometer (1.8 x m)

Dalton’s Atomic Theory John Dalton proposed an atomic theory (1808) 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.

Dalton’s Atomic Theory - Summary 1.matter is composed, indivisible particles (atoms) 2.all atoms of a particular element are identical 3.different elements have different atoms 4.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.

Problems with Dalton’s Atomic Theory? 1. matter is composed, indivisible particles Atoms Can Be Divided, but only in a nuclear reaction 2. 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 atoms YES! 4. atoms combine in certain whole-number ratios YES! 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

Plum Pudding Model Proposed by William Thomson (Lord Kelvin) (1890) Atom is a cloud of positive charge (pudding) Electrons scattered throughout (raisins)

The modern view of the atom was developed by Ernest Rutherford (1911).

Rutherford’s experiment.

Results of foil experiment if Plum Pudding model had been correct.

What Actually Happened

ATOM COMPOSITION protons and neutrons in the nucleus.protons and neutrons in the nucleus. the number of electrons is equal to the number of protons.the number of electrons is equal to the number of protons. electrons in space around the nucleus.electrons in space around the nucleus. extremely small. One teaspoon of water has 3 times as many atoms as the Atlantic Ocean has teaspoons of water.extremely small. One teaspoon of water has 3 times as many atoms as the Atlantic Ocean has teaspoons of water. The atom is mostly empty space

ATOMIC COMPOSITION Protons (p + )Protons (p + ) –+ electrical charge –mass = x g –relative mass = atomic mass units (amu) but we can round to 1 Electrons (e - )Electrons (e - ) – negative electrical charge –relative mass = amu but we can round to 0 Neutrons (n o )Neutrons (n o ) – no electrical charge –mass = amu but we can round to 1

Quarks What are Quarks?

Atomic Number, Z All atoms of the same element have the same number of protons in the nucleus, Z 13 Al Atomic number Atom symbol AVERAGE Atomic Mass

Mass Number, A Carbon-12 atom with 6 protons and 6 neutrons is the mass standardCarbon-12 atom with 6 protons and 6 neutrons is the mass standard = 12 atomic mass units= 12 atomic mass units Mass NumberMass Number (A) = # protons + # neutrons(A) = # protons + # neutrons NOT on the periodic table…(it is the AVERAGE atomic mass on the table)NOT on the periodic table…(it is the AVERAGE atomic mass on the table) A boron atom can haveA boron atom can have A = 5 p + 5 n = 10 amu A = 5 p + 5 n = 10 amu

Isotopes Atoms of the same element (same Z) but different mass number (A).Atoms of the same element (same Z) but different mass number (A). Boron-10 ( 10 B) has 5 p and 5 nBoron-10 ( 10 B) has 5 p and 5 n Boron-11 ( 11 B) has 5 p and 6 nBoron-11 ( 11 B) has 5 p and 6 n 10 B 11 B

Figure 3.10: Two isotopes of sodium.

Isotopes & Their Uses Bone scans with radioactive technetium-99.

Isotopes & Their Uses The tritium content of ground water is used to discover the source of the water, for example, in municipal water or the source of the steam from a volcano.

Isotopic 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 form mass number 23 Na atomic number 11

Isotopes? Which of the following represent isotopes of the same element? Which element? 234 X 234 X 235 X 238 X

Counting Protons, Neutrons, and Electrons Protons: Atomic Number (from periodic table) Identifies element Neutrons: Mass Number – Atomic Number Isotopes vary based on this number Electrons: In a neutral atom, electrons = protons Removing or adding electrons form an ion Responsible for bonding behavior

Learning Check – Counting Naturally occurring carbon consists of three isotopes, 12 C, 13 C, and 14 C. State the number of protons, neutrons, and electrons in each of these carbon atoms. 12 C 13 C 14 C #p + _______ _______ _______ #n o _______ _______ _______ #e - _______ _______ _______

Answers 12 C 13 C 14 C #p #n o #e

Learning Check An atom has 14 protons and 20 neutrons. A.Its atomic number is 1) 142) 163) 34 B. Its mass number is 1) 142) 163) 34 C. The element is 1) Si2) Ca3) Se D.Another isotope of this element is 1) 34 X 2) 34 X 3) 36 X

AVERAGE ATOMIC MASS Because of the existence of isotopes, the mass of a collection of atoms has an average value.Because of the existence of isotopes, the mass of a collection of atoms has an average value. Boron is 20% 10 B and 80% 11 B. That is, 11 B is 80 percent abundant on earth.Boron is 20% 10 B and 80% 11 B. That is, 11 B is 80 percent abundant on earth. For boron atomic weightFor boron atomic weight = 0.20 (10 amu) (11 amu) = 10.8 amu = 0.20 (10 amu) (11 amu) = 10.8 amu 10 B 11 B

Isotopes & Average Atomic Mass AVG Atomic Mass =AVG Atomic Mass = (Isotope 1 Mass x Isotope 1 Abundance) + (Isotope 2 Mass x Isotope 2 Abundance) … 6 Li = 7.5% abundant and 7 Li = 92.5% 6 Li = 7.5% abundant and 7 Li = 92.5% –Avg. Atomic mass of Li = ______________ 28 Si = 92.23%, 29 Si = 4.67%, 30 Si = 3.10% 28 Si = 92.23%, 29 Si = 4.67%, 30 Si = 3.10% –Avg. Atomic mass of Si = ______________

IONS IONS are atoms or groups of atoms with a positive or negative charge.IONS are atoms or groups of atoms with a positive or negative charge. Taking away an electron from an atom gives a CATION with a positive chargeTaking away an electron from an atom gives a CATION with a positive charge Adding an electron to an atom gives an ANION with a negative charge.Adding an electron to an atom gives an ANION with a negative charge. To tell the difference between an atom and an ion, look to see if there is a charge in the superscript! Examples: Na + Ca +2 I - O -2To tell the difference between an atom and an ion, look to see if there is a charge in the superscript! Examples: Na + Ca +2 I - O -2 Na Ca I O Na Ca I O

Forming Cations & Anions A CATION forms when an atom loses one or more electrons. An ANION forms when an atom gains one or more electrons Mg --> Mg e- F + e- --> F -

PREDICTING ION CHARGES In general metals (Mg) lose electrons ---> cationsmetals (Mg) lose electrons ---> cations nonmetals (F) gain electrons ---> anionsnonmetals (F) gain electrons ---> anions

Learning Check – Counting State the number of protons, neutrons, and electrons in each of these ions. 39 K + 16 O -241 Ca #p + ___________________ #n o ___________________ #e - ___________________

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 - ___________

Charges on Common Ions By losing or gaining e-, atom has same number of e-’s as nearest Group 8A atom.

53 Most elements are very reactive. Elements are not generally found in uncombined form.  Exceptions are: »Noble metals – gold, platinum and silver »Noble gases – Group 8 Natural States and Elements Helium Neon Argon Krypton Xenon

54 Diatomic Molecules Nitrogen gas contains N 2 molecules. Oxygen gas contains O 2 molecules. Section 4.9 Natural States and Elements

Copyright © Cengage Learning. All rights reserved 55 Diatomic Molecules Section 4.9 Natural States and Elements

56 Nonmetals Liquid Nitrogen Selenium Phosphorus Bromine Chlorine Fluorine Sulfur Graphite

57 Different forms of a given element. Example:  Solid carbon occurs in three forms. »Diamond »Graphite »Buckminsterfullerene Carbon Allotropes Section 4.9 Natural States and Elements