General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 1 Elements are  pure substances that cannot be separated into simpler substances by ordinary laboratory processes  the building blocks of matter gold carbon aluminum Elements

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 2 A symbol  represents the name of an element  consists of 1 or 2 letters  starts with a capital letter Examples: 1-Letter Symbols 2-Letter Symbols C carbon Co cobalt N nitrogenCa calcium F fluorine Al aluminum O oxygen Mg magnesium Symbols of Elements

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 3 Groups and Periods (continued)

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 4 Representative Elements  Several groups of representative elements are known by common names.

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 5 Metals, Nonmetals, and Metalloids The heavy zigzag line separates metals and nonmetals.  Metals are located to the left.  Nonmetals are located to the right.  Metalloids are located along the heavy zigzag line between the metals and nonmetals.

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 6 Metals  are shiny and ductile  are good conductors of heat and electricity Nonmetals  are dull, brittle, and poor conductors of heat and electricity  are good insulators Metalloids  are better conductors than nonmetals, but not as good as metals  are used as semiconductors and insulators Properties of Metals, Nonmetals, and Metalloids

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 7 Subatomic Particles Atoms contain subatomic particles.  Protons have a positive (+) charge.  Electrons have a negative (–) charge.  Like charges repel, and unlike charges attract.  Neutrons are neutral.

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 8 The atomic number  is specific for each element  is the same for all atoms of an element  is equal to the number of protons in an atom  appears above the symbol of an element Atomic Number 11 Na Atomic Number Symbol

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 9 An atom  of an element is electrically neutral; the net charge of an atom is zero  has an equal number of protons and electrons. number of protons = number of electrons  of aluminum has 13 protons and 13 electrons; the net charge is zero 13 protons (13+) + 13 electrons (13–) = 0 Number of Electrons in an Atom

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 10 Mass Number The mass number  represents the number of particles in the nucleus.  is equal to the number of protons + number of neutrons

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 11 Isotopes  are atoms of the same element that have different mass numbers  have the same number of protons but different numbers of neutrons Isotopes

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 12 A nuclear symbol  represents a particular atom of an element  gives the mass number in the upper left corner and the atomic number in the lower left corner Example: An atom of sodium with atomic number 11 and a mass number 23 has the following atomic symbol: mass number atomic number Nuclear Symbol Na

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 13 For an atom, the nuclear symbol gives the number of  protons (p + )  neutrons (n)  electrons (e – ) 8 p + 15 p + 30 p + 8 n16 n35 n 8 e – 15 e – 30 e – Nuclear Symbols 16 8 O P Zn

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 14 Isotopes of Sulfur A sample of naturally occurring sulfur contains several isotopes with the following abundances: Isotope % Abundance S S S S S SSS

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 15 Electromagnetic Radiation Electromagnetic radiation  is energy that travels as waves through space  is described in terms of wavelength and frequency  moves at the speed of light in a vacuum speed of light = 3.0 x 10 8 m/s

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 16 Electromagnetic Spectrum The electromagnetic spectrum  arranges forms of energy from lowest to highest  arranges energy from longest to shortest wavelengths  shows visible light with wavelengths from 700–400 nm

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 17 Example of Atomic Spectra

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 18 Electron Energy Levels Electrons are arranged in specific energy levels that  are labeled n = 1, n = 2, n = 3, and so on  increase in energy as n increases  have the electrons with the lowest energy in the first energy level (n = 1) closest to the nucleus

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 19 Energy Level Changes  An electron absorbs energy to “jump” to a higher energy level.  When an electron falls to a lower energy level, energy is emitted.  In the visible range, the emitted energy appears as a color.

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 20 Sublevels  contain electrons with the same energy  are found within each energy level.  are designated by the letters s, p, d, and f The number of sublevels is equal to the value of the principal quantum number (n).

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 21 Number of Sublevels

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 22 Energy of Sublevels In any energy level  the s sublevel has the lowest energy  the s sublevel is followed by the p, d, and f sublevels (in order of increasing energy)  higher sublevels are possible, but only s, p, d, and f sublevels are needed to hold the electrons in the atoms known today

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 23 Orbitals An orbital  is a three-dimensional space around a nucleus where an electron is most likely to be found  has a shape that represents electron density (not a path the electron follows)  can hold up to 2 electrons  contains two electrons that must spin in opposite

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 24 s Orbitals An s orbital  has a spherical shape around the nucleus  increases in size around the nucleus as the energy level n value increases  is a single orbital found in each s sublevel

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 25 p Orbitals A p orbital  has a two-lobed shape  is one of three p orbitals that make up each p sublevel  increases in size as the value of n increases

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 26 Sublevels and Orbitals Each sublevel consists of a specific number of orbitals.  An s sublevel contains one s orbital.  A p sublevel contains three p orbitals.  A d sublevel contains five d orbitals.  An f sublevel contains seven f orbitals.

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. Electron configuration is how the electrons are distributed among the various atomic orbitals in an atom. 1s 1 principal quantum number n angular momentum quantum number l number of electrons in the orbital or subshell Orbital diagram H 1s 1 7.8

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. Order of orbitals (filling) in multi-electron atom 1s < 2s < 2p < 3s < 3p < 4s < 3d < 4p < 5s < 4d < 5p < 6s 7.7

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 29 An orbital diagram shows  orbitals as boxes in each sublevel  electrons in orbitals as vertical arrows  electrons in the same orbital with opposite spins (up and down vertical arrows) Example: Orbital diagram for Li 1s 2 2s 1 2p filled half-filled empty Orbital Diagrams

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 30 An electron configuration  lists the sublevels filling with electrons in order of increasing energy  uses superscripts to show the number of electrons in each sublevel Electron Configuration

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. “Fill up” electrons in lowest energy orbitals (Aufbau principle) H 1 electron H 1s 1 He 2 electrons He 1s 2 Li 3 electrons Li 1s 2 2s 1 Be 4 electrons Be 1s 2 2s 2 B 5 electrons B 1s 2 2s 2 2p 1 C 6 electrons ?? 7.9

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 32 Abbreviated Configurations An abbreviated configuration shows  the symbol of the noble gas in brackets that represents completed sublevels  the remaining electrons in order of their sublevels Example: Chlorine has a configuration of 1s 2 2s 2 2p 6 3s 2 3p 5 [Ne] The abbreviated configuration for chlorine is [Ne]3s 2 3p 5

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 33 Sublevel Blocks

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 34 Using the periodic table, give the atomic mass of each element. A. calcium__________ B. aluminum__________ C. lead__________ D. barium__________ E. iron__________ Learning Check

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 35 Using the periodic table, give the atomic mass of each element. A. calcium40.08 amu B. aluminum26.98 amu C. lead207.2 amu D. barium137.3 amu E. iron55.85 amu Solution

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 36 Learning Check 1. Which of the following has the shortest wavelength? A. microwaves B. blue light C. UV light 2. Which of the following has the lowest energy? A. red light B. blue lightC. green light

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 37 Solution 1. Which of the following has the shortest wavelength? C. UV light 2. Which of the following has the lowest energy? A. red light

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 38 In each of the following energy level changes, indicate if energy is 1) absorbed, 2) emitted, or 3) not changed. A. An electron moves from the first energy level (n = 1) to the third energy level (n = 3). B. An electron falls from the third energy level to the second energy level. C. An electron moves within the third energy level. Learning Check

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 39 In each of the following energy level changes, indicate if energy is 1) absorbed, 2) emitted, or 3) not changed. A. An electron in an atom moves from the first energy level (n = 1) to the third energy level (n = 3). 1) absorbed B. An electron falls from the third energy level to the second energy level. 2) emitted C. An electron moves within the third energy level. 3) not changed Solution

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 40 Valence Electrons The valence electrons  determine the chemical properties of the elements  are the electrons in the outermost, highest energy level  are related to the Group number of the element Example: Phosphorus has 5 valence electrons. 5 valence electrons P Group 5A(15) 1s 2 2s 2 2p 6 3s 2 3p 3

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 41 All the elements in a group have the same number of valence electrons. Example: Elements in Group 2A(2) have two (2) valence electrons. Be1s 2 2s 2 Mg 1s 2 2s 2 2p 6 3s 2 Ca [Ar]4s 2 Sr [Kr]5s 2 Groups and Valence Electrons

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 42 Electron-Dot Symbols An electron-dot symbol  indicates valence electrons as dots around the symbol of the element  of Mg shows two valence electrons as single dots on the sides of the symbol Mg · · Mg · or Mg · or · Mg or · Mg ·

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 43 Writing Electron-Dot Symbols The electron-dot symbols for  Groups 1A(1) to 4A(14) use single dots · · Na · · Mg · · Al · · C · ·  Groups 5A(15) to 7A(17) use pairs and single dots. · · · · · P · : O · ·

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 44 Groups and Electron-Dot Symbols  in a group, all the electron-dot symbols have the same number of valence electrons (dots). Example: Atoms of elements in Group 2A(2) each have 2 valence electrons. 2A(2) · Be · · Mg · · Ca · · Sr · · Ba ·

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 45 Atomic Size Atomic size  is described using the atomic radius  is the distance from the nucleus to the valence electrons  increases going down a group  decreases going across a period from left to right

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 46 Atomic Size (continued)

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 47 Atomic Radius Within A Group Atomic radius  increases going down a group

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 8.3

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 49 Ionization Energy Ionization energy  is the energy it takes to remove a valence electron from an atom in the gaseous state Na(g) + Energy (ionization) Na + (g) + e –

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. General Trend in First Ionization Energies 8.4 Increasing First Ionization Energy

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 51 Write the orbital diagrams for A. nitrogen B. oxygen C. magnesium Learning Check

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 52 Write the orbital diagrams for A. nitrogen 1s 2s 2p B. oxygen 1s 2s 2p C. magnesium 1s 2s 2p 3s Solution

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 53 Write the electron configuration and abbreviated configuration for each of the following elements: A. Cl B. S C. K Learning Check

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 54 A. Cl 1s 2 2s 2 2p 6 3s 2 3p 5 [Ne]3s 2 3p 5 B. S 1s 2 2s 2 2p 6 3s 2 3p 4 [Ne]3s 2 3p 4 C. K 1s 2 2s 2 2p 6 3s 2 3p 6 4s 1 [Ar]4s 1 Solution

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 55 Learning Check Give the symbol of the element that has A. the abbreviated configuration [Ar]4s 2 3d 6 B. four 3p electrons C. two electrons in the 4d sublevel D. the electron configuration 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 2

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 56 State the number of valence electrons for each. A. O 1) 42) 63) 8 B. Al 1) 132) 33) 1 C. Cl 1) 22) 53) 7 Learning Check

General, Organic, and Biological Chemistry Copyright © 2010 Pearson Education, Inc. 57 State the number of valence electrons for each. A. O 2) 6 B. Al 2) 3 C. Cl 3) 7 Solution