Zumdahl De Coste World of CHEMISTRY Chapter 3

Chapter 3 Chemical Foundations: Elements, Atoms, and Ions Copyright© by Houghton Mifflin Company. All

Top Ten Copyright© by Houghton Mifflin Company. All rights reserved. 3

* An ELEMENT is the simplest form of a substance that can not be

Table 3. 1 Copyright© by Houghton Mifflin Company. All rights reserved. 5

The 9 elements that account for 98% of the earths total mass (table 3.

* Names of the elements originated mainly from GREEK. LATIN, and GERMAN. * We

Table 3. 3 Copyright© by Houghton Mifflin Company. All rights reserved. 8

Dalton's Atomic Theory 1. Elements are made of tiny particles called atoms 2. All

Figure 3. 2: Representation of NO, NO 2, and N 2 O. Copyright© by

Rules for Writing Formulas 1. Each atom present is represented by its element symbol.

J. J Thomson concluded that all atoms contain negative particles called electrons and must

Figure 3. 3: Plum Pudding model of an atom. Copyright© by Houghton Mifflin Company.

Figure 3. 5: Rutherford’s experiment. Copyright© by Houghton Mifflin Company. All rights reserved. 15

Figure 3. 6: Results of foil experiment if Plum Pudding model had been correct.

Figure 3. 6: Actual Results. Copyright© by Houghton Mifflin Company. All rights reserved. 17

Figure 3. 7: Schematic of a cathode ray tube. Copyright© by Houghton Mifflin Company.

Atoms can be divided into 3 subatomic Particles: 1. Protons 2. Neutrons 3. Electrons

Figure 3. 9: A nuclear atom viewed in cross section. Copyright© by Houghton Mifflin

Figure 3. 10: Two isotopes of sodium. Copyright© by Houghton Mifflin Company. All rights

ATOMIC NUMBER means the number of protons in an element MASS NUMBER means the

Isotopes are atoms of the same element that have different numbers of neutrons. Isotopes

-Ion: An element, or atom, with a charge. Either positive or negative. Elements receive

Figure 3. 19: The ions formed by selected members of groups 1, 2, 3,

Figure 3. 20: Pure water does not conduct a current. Copyright© by Houghton Mifflin

Figure 3. 20: Water containing dissolved salt conducts a current. Copyright© by Houghton Mifflin

The known elements were organized according to their atomic masses in 1871 by MENDELEEV.

Figure 3. 11: The periodic table. Copyright© by Houghton Mifflin Company. All rights reserved.

All Elements can be divided into three main categories: 1. Metals 2. Nonmetals 3.

Figure 3. 12: Elements classified as metals and nonmetals. Copyright© by Houghton Mifflin Company.

The upper right hand corner of the Table is where the NONMETALS are found,

The Metalloids are the 6 elements: B, Si, Ge, As, Sb, and Te *

The most important metalloid is Silicon, which is use to make computer chips

Group 1 Elements are also called ALKALI METALS Examples are: Li, Na, K, Rb,

Group 17 Elements are called the HALOGENS Examples are F, Cl, Br, I, A

ALKALI METALS - are very Reactive, which means they readily combine with other elements.

ALKALINE EARTH METALS - they are reactive, but not as reactive as the alkali

Alkali Metals and Alkaline Earth Metal have been used in everyday items such as:

The Halogens * are non-metals and exist as diatomic molecules ( a molecule that

Halogens are reactive and react with Hydrogen gas to form compounds with the formula

Figure 3. 14: Nitrogen gas contains NXN molecules. Copyright© by Houghton Mifflin Company. All

Figure 3. 14: Oxygen gas contains OXO molecules. Copyright© by Houghton Mifflin Company. All

Noble Gases: - They are all colorless gases at 25°C. - They are unreactive

Figure 3. 13: A collection of argon atoms. Copyright© by Houghton Mifflin Company. All

Table 3. 5 Copyright© by Houghton Mifflin Company. All rights reserved. 46

Figure 3. 15: The decomposition of two water molecules. Copyright© by Houghton Mifflin Company.

Figure 3. 17: Spherical atoms packed closely together. Copyright© by Houghton Mifflin Company. All

Terms to Know: Melting Point: goes from solid to liquid Freezing point: goes from

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Zumdahl De. Coste World of CHEMISTRY

* An ELEMENT is the simplest form of a substance that can not be broken down. * A COMPOUND is two or more elements bound together. **Presently there are 115 elements, 88 of which occur naturally.

The 9 elements that account for 98% of the earths total mass (table 3. 1) * Oxygen * Silicon * aluminum * Iron * calcium * sodium * potassium * magnesium * hydrogen

* Names of the elements originated mainly from GREEK. LATIN, and GERMAN. * We abbreviate the elements to simplify. -Always us a CAPITAL letter for the first letter in element. -use lower case if there is a second letter. Ex: Hydrogen = H Gold = Au (Aurum is latin for shiny)

Dalton's Atomic Theory 1. Elements are made of tiny particles called atoms 2. All atoms of a given element are identical 3. Atoms of a given element are different from those of any other element. 4. Atoms of one can combine with atoms of another to form compounds 5. Atoms are indivisible in chemical processes, they are not created or destroyed.

Rules for Writing Formulas 1. Each atom present is represented by its element symbol. 2. The number of each type of atom is indicated by a subscript written to the right of the element symbol. 3. When only one atom of a given type is present, the subscript 1 is not written. Copyright© by Houghton Mifflin Company. All rights reserved. 12

J. J Thomson concluded that all atoms contain negative particles called electrons and must then also contain positive particles called protons. William Thompson was for the PLUM-PUDDING model. He said the atom was like plum pudding ( bowl of pudding with things floating in it). Atom has pudding of positive and negative charges scattered around to counter balance. Rutherford found that atoms must have a nucleus with a dense positive charge. He concluded that the nucleus contains protons, which are positive charge, and also neutrons which have no charge.

Atoms can be divided into 3 subatomic Particles: 1. Protons 2. Neutrons 3. Electrons Particle Symbol Charge Mass location Proton P + 1 nucleus Neutron N 0 1 Nucleus Electron E - 1/1800 orbits

ATOMIC NUMBER means the number of protons in an element MASS NUMBER means the number of Neutrons and Protons in the element Ex: Na 23_____mass number 11_____Atomic Number

Isotopes are atoms of the same element that have different numbers of neutrons. Isotopes have the same atomic number, but different mass number

-Ion: An element, or atom, with a charge. Either positive or negative. Elements receive charges by the movement or transfer of electrons. **-If electrons are lost, they become positive. This is called a CATION. Ex. Mg 2+ -**if electrons are gained, they become negative. This is called an ANION. Ex. Cl -1 -Charges are represented with superscript numbers. Ionic Compounds contain a metal and non-metal. -Net Charges must always equal zero.

The known elements were organized according to their atomic masses in 1871 by MENDELEEV. The modern version of his table is called THE PERIODIC TABLE OF CONTENTS The Horizontal rows are called PERIODS The vertical columns are called GROUPS The Main Group Elements are in groups 1, 2, 13, 14, 15, 16, 17, and 18 Transition Metals are elements in groups 3 -12

All Elements can be divided into three main categories: 1. Metals 2. Nonmetals 3. Metalloids

The upper right hand corner of the Table is where the NONMETALS are found, including Hydrogen Properties of NONMETALS: 1. poor conductors of HEAT and ELECTRICITY 2. Do Not have a shiny appearance or reflect light well 3. are brittle in the solid form

The Metalloids are the 6 elements: B, Si, Ge, As, Sb, and Te * sometimes called semi-metals -They separate the metals and non-metals and be found hugging the staircase line. -Properties: -1. poor conductors of heat -2. semi-conductors of electricity -3. have a dull appearance and do not reflect light as well -4. are brittle solids at 25° C.

The most important metalloid is Silicon, which is use to make computer chips

Group 1 Elements are also called ALKALI METALS Examples are: Li, Na, K, Rb, Cs, and Fr. Group 2 Elements are ALKALINE EARTH METALS Examples are: Be, Mg, Ca, Sr, Ba, and Ra

Group 17 Elements are called the HALOGENS Examples are F, Cl, Br, I, A Group 18 elements are called NOBLE GASES (or inert gases, or rare gases) Examples are : He, Ne, Ar, Kr, Xe, Rn

ALKALI METALS - are very Reactive, which means they readily combine with other elements. ** React with chlorine gas to form a metal chloride ** React with water to form hydrogen gas

ALKALINE EARTH METALS - they are reactive, but not as reactive as the alkali metals. ** react with chlorine gas to form a metal chloride ** react with water to form hydrogen gas (sodium reacts with water at room temperature, but magnesium won’t react with water unless the water is boiling. )

Alkali Metals and Alkaline Earth Metal have been used in everyday items such as: *Lithium was used to treat manic depression -7 -UP used to contain lithium *Magnesium is used in disposable flash bulbs *Calcium can be found in limestone, chalk, marble, and coral.

The Halogens * are non-metals and exist as diatomic molecules ( a molecule that contains 2 atoms. - Homonuclear diatomic molecules are the same element F 2, Cl 2, Br 2, and I 2 -Heteronuclear diatomic molecules are different CO, NO, elements:

Halogens are reactive and react with Hydrogen gas to form compounds with the formula (HX) Ex. -HF is used to etch glass (lightbulbs, TV tubes) -HCl is used to digest food

Noble Gases: - They are all colorless gases at 25°C. - They are unreactive (very stable) Ex: Neon, used in neon signs (zapped by electricity)

Terms to Know: Melting Point: goes from solid to liquid Freezing point: goes from liquid to solid Evaporation: Condensation: goes from liquid to gas goes from gas to liquid Sublimation: goes from solid to gas Deposition: goes from gas to solid