The Periodic Table

Periods: Periods are the rows in the periodic table. The period tells you the energy level. D block energy levels = period – one F block energy levels = period - two

Groups: Groups are the columns in the periodic table All group members have the same number of valence (Outermost energy level) electrons. The group number (usually) tells you the number of valence electrons. All group members have the same number of valence electrons so they reactive similarly. For this reason, groups are often called families.

Changes to the groups Take the ones off 13 to 18 to make them 3 to 8

Group 1: The Alkali Metal Family (Does not include Hydrogen) The alkali metals are the most reactive metals These metals react strongly with water. Alkali metals are rarely found by themselves in nature since they are so reactive.

Group 2: Alkaline Earth Metal Family These metals are less reactive than the alkali metals but still make compounds easily.

Groups 3-12: The Transition Metals These metals have their outermost electrons in the d sublevel.

Group 7: Halogen Family Group 7 contains the most reactive non-metals. The halogens need one more electron to have a completed energy level, so they react easily to get the electron

Group 8: The Noble Gas Family The Noble gases do not react with other elements. The Noble gases have completely filled energy levels, so they don’t need to react to get or give away electrons. Noble gasElectron Configuration Helium1s 2 Neon1s 2 2s 2 2p 6 Argon1s 2 2s 2 2p 6 3s 2 3p 6

Metals, non-metals, metalloids, and the staircase. The “staircase” on the periodic table separates metals, non-metals, and metalloids

Metals Metals are to the left of the staircase and have these properties: Malleable: Easily molded. Conductive: Carry heat or electricity. Ductile: Easily pulled into wires. Lustrous: Shiny

Non-metals Non-metals are to the right of the staircase and have these properties: Brittle: Falls apart easily. Not conductive: Not ductile: Dull Usually gases at room temperature

Metalloids Metalloids surround the staircase: The metalloids have properties of both metals and non-metals.

Hydrogen Hydrogen has the properties of a non-metal, even though it is shown on the left side of the periodic table with the metals. When it comes to bonding, Hydrogen acts (mostly) like a metal: It gives up its electron.

Some trends in the periodic table: Atomic Radius As you move down a group in the periodic table, you are adding more and more energy levels. As you add more energy levels, what happens to the size of the atom? The atoms get bigger as you move down groups in the periodic table. In chemistry, we measure the size of atoms using atomic radius So, the atomic radius increases as you move down groups in the periodic table

Some trends in the periodic table: Atomic Radius As you move across a period in the periodic table, you are adding more and more protons to the nucleus of the atom. As you add more protons, what happens to the electrons? Are they more attracted to the nucleus or less attracted? The electrons are more attracted to the nucleus so they pull in closer to the nucleus. What happens to the size of the atom? So, the atomic radius decreases as you move across periods in the periodic table

The other periodic trends depend on atomic radius, or the size of the atom. So make sure you know: Atomic radius (size) increases as you go down a group, since you’re adding energy levels. Atomic radius (size) decreases as you go across a period since the increasing number of protons pull the electrons in closer. So what’s the biggest atom? Francium What’s the smallest atom? Helium

Ionization energy Ionization energy is the amount of energy it takes to pull an electron off of an atom. So ionization energy is a measurement of how hard it is to pull an electron off an atom. Is it easier to steal something if its far from its owner or close? So from which atoms is it hardest to pull electrons off? The smallest So which element’s atom has the highest ionization energy? Or is hardest to steal electrons from? Helium, the smallest Which element’s atom has the lowest ionization energy? Or is easiest to steal electrons from? Francium, the biggest

Electronegativity Electronegativity is an atom’s ability to pull (steal) an electron off of another atom. So electronegativity is a measurement of how good an electron thief (or how good an electron puller) an atom is (4.0 is best, 0.0 worst). Is it easier to steal something if you’re small or big? So from which atoms are the best electron thiefs? The smallest, because the positive nucleus is closer to the other atom to attract its electrons. It’s important to remember, at this point, that the noble gases are “satisfied” with the electrons they have and don’t steal electrons. So which element’s atom has the highest electronegativity? Or is best at stealing electrons? Fluorine, the smallest non noble gas. Which element’s atom has the lowest electronegativity? Or is the worst electron thief? Francium, the biggest