DO NOW “Unknown” element, Rx, is a non metal Rx has similar chemical properties to Fluorine (F) and Iodine (I). Rx’s atomic # is greater than Argon (Ar), but less than Krypton (Kr).  What element must Rx be?

Non metals Are In this corner In green

Trends are:  Predictable ways in which something changes Atomic Radius  Trend in the size  of an atom Ionic Radius  Trend in the size  of ions of an atom Periodic Table Trends

Trends: Atomic Radius An atom’s size is determined by the space occupied by its e- cloud

Turn to p.188 – Atomic Radius Generally decreases Generally increases Size of atoms of elements of the periodic table (atomic radius)

Atomic radius: see if you can tell who is bigger? 1.Put Group 2 in order Smallest to largest: Sr Be Mg Ca 2.Put Group 1 in order Smallest to largest: Na Li H K Rb 3.Put these elements From Period 5 in order smallest To largest: Xe Cd Mo Zr Rb A trend is a predictable change you can see. So fill in the blanks with the choices: As you go down a group (column) the atomic radius (increases/decreases) ______________________. As you go across a period (row) the atomic radius (increases/decreases) ____________________.

What do you notice as you move from left to right? Do you have more or less e- as you move from left to right? The size _________ because: Trends in periods The atomic radius gets smaller as you move from left to right Elements in the same period have the same highest (principal) energy level. e- AND protons are added (atomic # increases) Nucleus has more power to pull e- in principal energy level closer to nucleus (= smaller radius) decreases Less e-

Trends in groups What trend(s) do you notice as you move from top to bottom? Do you have more or less e- as you move from top to bottom? The atomic radius gets _________ because: The atomic radius gets larger as you move from top to bottom More larger Each atom has the same # of e- in their valence shell, but the highest (principal) energy level has increased by 1 each time you move down. (You would need to draw an additional shell around the nucleus.)

Examples Using only your notes and a periodic table, which would have a bigger atomic radius? He / Ar K / Ar Fe / Br Ar K Fe Mg / SMg

Ionic Radius Size of radius of an atom after it has gained or lost electrons to get a full shell (lucky 8).  Remember: Stability is achieved by having a full valence shell. The ionic radius becomes:  Smaller = When e- are lost  Larger = When e- are gained e- gainede- lost

Ionic Radius, p. 190 A trend is a predicable pattern. Which is a trend: 1. Ion size increases L to R across a period 2. Ion size increases top to bottom for groups 1 and 2

Review: Metals, Nonmetals, Metalloids

DO NOW Energy Level Element # 1 ELECTRONS Element # 2 ELECTRONS Element # 3 ELECTRONS 1 st 1s nd 2s 2p rd 3s 3p Can you tell what elements are shown here? 2.Can you tell which is a noble gas and which is an alkali metal? 3.How could you tell which one is a metal?

Three Classes of Elements: Metals- Loose e- easily! Good conductors high luster or sheen Solid at room temperature (except Mercury) Ductile- drawn into wire Malleable- Able to bend, hammered into thin sheets without breaking

Three Classes of Elements: Nonmetals- Poor conductors (Carbon is exception) Most are gases at room temperature Properties opposite of metals.  Non-malleable  Non-ductile Brittle (break easily)

Three Classes of Elements: Metalloids- Properties similar to both metals and nonmetals Depends on the conditions  Temperature  Pressure  Found where the metals and nonmetals meet on the periodic table.

DO NOW Atom# Protons # Electron s # Neutron s How many elements are shown here? 2. Are any of these isotopes of each other? 3. How can you tell?

Isotopes BrainPop! Ions are formed when an atom gains or looses: protons neutrons e- Isotopes are formed when an atom looses: protons neutrons e- What is formed when an atom looses a proton?  A different element!  Remember: The atomic # is determined by the # of protons in an atom’s nucleus!

Isotopes cont. Naturally occur, some more common than others The atomic mass of an element is determined by looking at the abundance of these different isotopes and calculating the average. THIS is why the atomic mass for the elements is not a whole #!!

Atomic # on bottom Mass #