Day Which metal would you expect to be more reactive - Fr OR Cu? WHY? 2.Which nonmetal would you expect to be more reactive - F OR Ne? WHY?
How is the periodic table arranged?
Periodic Trends Atomic radius: - Measure of size – radius of an atom - Atoms with more electrons do NOT necessarily have a larger atomic radius
Periodic Trends - Atoms with more electrons do NOT necessarily have a larger atomic radius
Periodic Trends - Atoms with more electrons do NOT necessarily have a larger atomic radius 1. Atoms get larger going down a group. 2. Atoms get smaller going across a period So why?...
Periodic Trends - Atoms with more electrons do NOT necessarily have a larger atomic radius As you move down a group you increase the number of energy levels in the atom and so the atom gets larger as expected.
Periodic Trends - Atoms with more electrons do NOT necessarily have a larger atomic radius As you move across a period, # of protons increases and outermost energy level stays the same, the attractive force between elecs. and pros. pulls the atom tighter (closer to nucleus)
Periodic Trends What’s bigger: B or Al B or N N or Zn C or Cl
Red = ? Green = ? Blue = ?
Good Conductors = ?Inert elements = ?
Review 1. What element is in Group 2, Period 3? 2. Name an element in Group 3 3. How many valence electrons in Xe? 4. Give me an element with 1 valence electron.
Alkali metals 7 valence Nonmetals Magnesium Ductile Halogens 1 valence Noble gases Atomic radius Period 3
metalloids inert fluorine malleable Helium Halogens 1 valence Noble gases Atomic radius Period 3
Day Why does the size of an atom decrease moving across a period? 2.What is more reactive Cl or Ar – Explain!!!
Red = ? Green = ? Blue = ?
Good Conductors = ?Inert elements = ?
Review 1. What element is in Group 2, Period 3? 2. Name an element in Group 3 3. How many valence electrons in Xe? 4. Give me an element with 1 valence electron.
Partner Review 1. What element is in Group 17, Period 3? 2. What family of elements is the element above in? 3. How many valence electrons does it have?
Periodic Trends What are ions? - atoms that are charged due to the loss or gain of electrons - If an atom loses elecs. it becomes smaller and positive - If an atom gains elecs. it becomes larger and negative Notes page 4
Periodic Trends What are ions? - If an atom loses elecs. it becomes smaller - If an atom gains elecs. it becomes larger PAGE Which elements gain elecs.? Which elements lose elecs.? Pattern?
Periodic Trends Elements on the right side of the periodic table form _________ ions Elements in the same group form ___________ ions negative The same
Periodic Trends What’s bigger: F or F - Na or Na + Na or Rb Na of Al F or Cl -
Read / review Section 6.2 and complete #s on page 173
Day Which halogen is found in period 2? 2.How many valence electrons does calcium have? 3.Why does the size of an atom increase moving down a group?
Octet rule – Atoms tend to gain, lose, or share electrons in order to acquire a full set of valence electrons (8) - 2 for H, He, Li, Be, + B notes page 6
As of today, you should have the following: Families colored in (page 168) Valence electrons marked +1, +2, -1,-2, and -3 ions marked Day 2 3-2
Valence electrons = Ions =
Add today: Reactivity trend (front / back) Atomic size (front / back) Positive and negative ion trend on back Day 2 3-2
Valence electrons = Ions = Atom size decreases Atom size increases Reactivity increases away from the middle
Positive and Negative ion trend Elements on the right side form negative ions. Elements on the left form positive ions.
Read / review Section 6.2 and complete #s on page 173