Atomic Structure and the Periodic Table

Early Models of the Atom Dalton’s Atomic Theory - All elements are composed of atoms - All elements are composed of atoms - All atoms of a given element are identical - All atoms of a given element are identical - Atoms of different elements are different - Atoms of different elements are different - Compounds consist of the atoms of different elements - Compounds consist of the atoms of different elements - Atoms are not created or destroyed in a chemical change - Atoms are not created or destroyed in a chemical change

Structure of the Nuclear Atom Thomson’s experiment- showed that atoms contained electrons

Plum Pudding Model

Structure of the Nuclear Atom Electron- negatively charged subatomic particle Electron- negatively charged subatomic particle Proton- positively charged subatomic particle found in the nucleus of the atom Proton- positively charged subatomic particle found in the nucleus of the atom Neutron- a subatomic particle with no charge that is found in the nucleus Neutron- a subatomic particle with no charge that is found in the nucleus

Structure of the Nuclear Atom Rutherford’s Experiment- showed that atoms have a dense nucleus Rutherford’s Experiment- showed that atoms have a dense nucleus

Rutherford’s Model

Structure of the Nuclear Atom Nucleus- contains protons and neutrons. Electrons orbit the nucleus Nucleus- contains protons and neutrons. Electrons orbit the nucleus

Comparing the Parts of the Atom

Bohr Model of the Atom Determined that electrons orbit the nucleus in specific energy levels Determined that electrons orbit the nucleus in specific energy levels Electron level Electron level Electrons in the level

Bohr Model

Distinguishing Between Atoms Atomic number- number of protons Atomic number- number of protons Practice- How many protons and electrons are in each atom? a. Fluorine b. Aluminum c. calcium

Distinguishing Between Atoms Mass number- sum of protons and neutrons Mass number- sum of protons and neutrons Practice- How many protons, electrons and neutrons are in the following atoms? Atomic Number Mass Number Atomic Number Mass Number a. Beryllium 4 9 b. Neon c. Sodium 11 23

Mass number – atomic number = neutrons Practice- How many neutrons are in each atom? a O b Ag c Pb

Distinguishing Between Atoms Isotopes- atoms with the same number of protons but different number of neutrons Isotopes- atoms with the same number of protons but different number of neutrons

Practice- The three isotopes of chromium are chromium-50, chromium-52, and chromium 53. How many neutrons are in each isotope, given that chromium always has an atomic number of 24?

Distinguishing Between Atoms Atomic mass- the weighted average of the masses of the isotopes of an element Atomic mass- the weighted average of the masses of the isotopes of an element - Atomic mass unit- a unit of mass equal to one-twelfth the mass of carbon twelve atom - Atomic mass unit- a unit of mass equal to one-twelfth the mass of carbon twelve atom

Calculating average atomic mass Average atomic mass = (fractional abundance of isotope 1)(mass of isotope 1) + (fractional abundance of isotope 2)(mass of isotope 2) Practice 1. Calculate the atomic mass of bromine. The two isotopes of bromine have atomic masses and relative abundances of amu (50.69%) and (49.31%)

Practice 2- Element X has two natural isotopes. The isotope with a mass of has a relative abundance of 19.91%. The isotope with a mass of has a relative abundance of 80.09%. Calculate the atomic mass of this element. Practice 3- Calculate the percent abundance of copper- 63 if the atomic mass is and the exact masses of the isotopes are amu and amu.

The Periodic Table Mendeleev- arranged the elements by increasing atomic mass Mendeleev- arranged the elements by increasing atomic mass

The Modern Periodic Table- shows all the known elements in order of increasing atomic number

The periodic table is organized to group elements with similar properties in vertical columns

The Modern Periodic Table Metals- elements on the left side of the table Metals- elements on the left side of the table - alkali metals- metals in group 1A - alkali metals- metals in group 1A - alkaline earth metals- metals in group 2A - alkaline earth metals- metals in group 2A - transition and inner transition metals- group B, located in the center of the table - transition and inner transition metals- group B, located in the center of the table Metalloids- have properties intermediate to metals and nonmetals Nonmetals- elements on the right side of the table - halogens- nonmetals in group 7A - halogens- nonmetals in group 7A - noble gases- elements in group 0 - noble gases- elements in group 0

Properties of the Metals 1. Conduct heat and electricity 2. Malleable (can be hammered into thin sheets) 3. Ductile (can be pulled into wires) 4. Lustrous (shiny)

Natural States of the Elements Diatomic Elements

BrINClHOF Elements- diatomic

Elemental Solids

The Modern Periodic Table Periods- horizontal rows on the periodic table Periods- horizontal rows on the periodic table Periodic law- when elements are arranged by increasing atomic number, there are periodic or repeating properties Periodic law- when elements are arranged by increasing atomic number, there are periodic or repeating properties Groups (families)- columns on the periodic table Groups (families)- columns on the periodic table - Group A elements- representative elements - Group A elements- representative elements - Group B elements- transition metals - Group B elements- transition metals