2Periodic TableNonmetals are on the right side of the periodic table (with the exception of H).
3Periodic TableMetals are on the left side of the chart.
4Periodic TableMetalloids border the stair-step line (with the exception of Al, Po, and At).
5Diatomic MoleculesThese seven elements occur naturally as molecules containing two atoms.
6Ions When atoms lose or gain electrons, they become ions. Cations are positive and are formed by elements on the left side of the periodic chart.Anions are negative and are formed by elements on the right side of the periodic chart.
7Development of Periodic Table Elements in the same group generally have similar chemical properties.Physical properties are not necessarily similar, however.
8Development of Periodic Table Dmitri Mendeleev and Lothar Meyer independently came to the same conclusion about how elements should be grouped.
9Metals versus Nonmetals Metals tend to form cations.Nonmetals tend to form anions.
10MetalsThey tend to be lustrous, malleable, ductile, and good conductors of heat and electricity.
11NonmetalsThese are dull, brittle substances that are poor conductors of heat and electricity.They tend to gain electrons in reactions with metals to acquire a noble gas configuration.
12MetalloidsThese have some characteristics of metals and some of nonmetals.For instance, silicon looks shiny, but is brittle and fairly poor conductor.
13Periodic TrendsIn this chapter, we will rationalize observed trends inSizes of atoms and ions.Ionization energy.Electronegativity
14What Is the Size of an Atom? The bonding atomic radius is defined as one-half of the distance between covalently bonded nuclei.Measured in nanometers
15Nuclear Charge The positive charge of the protons For example sodium has a nuclear charge of +11
16Sizes of Atoms Bonding atomic radius tends to… …decrease from left to right across a row…increase from top to bottom of a column
18Ionization EnergyThe ionization energy is the amount of energy required to remove an electron from the ground state of an atom.The first ionization energy is that energy required to remove first electron.The second ionization energy is that energy required to remove second electron, etc.Measured in J or kJ
19Ionization EnergyIt requires more energy to remove each successive electron.When all valence electrons have been removed, the ionization energy takes a quantum leap.
20Trends in First Ionization Energies As one goes down a column, less energy is required to remove the first electron.For atoms in the same group, Zeff is essentially the same, but the valence electrons are farther from the nucleus.
21Electronegativity A measure of how well you attract electrons. A scale of 0 – 4Created by Linus Pauling