Periodic Table Organization What determines the order the elements are in Atomic number and the number of protons Why is it such a funny shape Mendeleev organized elements according to their CHEMICAL traits ID: 436882
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Slide1
Please follow along on the worksheet I gave you.
Periodic TableSlide2
Organization
What determines the order the elements are in?
Atomic number and the number of protons
Why is it such a funny shape?
Mendeleev organized elements according to their CHEMICAL traits
Each column down has similar chemical properties
The column is called a family or groupSlide3
Groups/Families
Just like every family, a chemical family has traits in common, but each member is an individual
As you go down a family
What happens to the mass?
It increases
What happens to the number of total electrons?
The increase
What happens to the overall size of the atoms?
They increase
What happens to the number of VALANCE electrons?
They stay the same!
The further away from the nucleus the more they will react.
Which is more reactive, K or Na?
K is further down so it is more reactiveSlide4
Special Groups/Families
Group 1- is called the
alkali
metals
All have 1 valence electron.
Are they stable?
No, they like to get rid of the one e
-
and form an 1
+
ion
Group2- is called the
alkaline
-earth metals
All have 2 Valance electrons
Are they stable?
No, they want to get rid of two e
-
’s and form a 2+ ionSlide5
Group 17- is called the
halogen
family
All have 7 Valence e-’s
They want to gain ONE electron to be stable
Form -1 ions
Are they stable?
No they are very reactive and get more reactive as they get larger
These are NOT metalsGroup 18- has two names the Noble Gases or the Inert gasesHe has 2 valence e-’s.All the rest have 8 valance e-’s.Are they stable? YES! They do not chemically react.Every element is a gas at room temperature. They are NOT metals
`Slide6
What about all the other columns?
Each element in a group shares the same number of valance e
-
’s.
This allows us to predict how each will react.
Groups 3- 12 are called the Transition
metals
As you move across they are going from being the most metallic to least metallicSlide7
Metals
Metals have special PHYSICAL properties
Shiny- absorb and reflect light
Ductile- made into wire
Malleable – can be shaped
All are solid at room temperature except Hg
Conductors of heat and electricity (means they can move the energy from one place to another.)
Most metals have 3-6 valance e
-’s. When the e- from one atom moves, it will cause a neighbor e- to move. They all “jumble together”. The total number of electrons is the same, but they move from atom to atom. We call them “free floating.”Slide8
Non-metals
Not very many of these.
They are all on the right hand side of the Table.(Except for H gas.)
They like to gain electrons or share electrons.
They are brittle and reactive.
Groups 17 and 18 are the only two columns that have all non-metals in themSlide9
Metalloids
Elements that are right between the metals and non-metals.
The temperature, pressure and other substances around them will determine how they react.
There are seven metalloids.
The common ones are boron B, arsenic As, and silicon Si
Other four are germanium Ge, antimony
Sb
, and Tellurium
Te, Polonium Po Slide10
Horizontal Organization
The rows are called Periods.
As you go across the period, the atoms gain ONE proton.
Period 1 has only H and He
Period 2 has Li, Be, B, C, N, O, F and Ne
Each Period starts with an element with 1 valance electron
Each Period ends with a NOBLE GAS! A very stable element!
Think of the Group 18, being the period at the end of a sentence. We need to start the new sentence and so must go start all over again with one valance e
-.As you move across the PERIOD, the atoms get smaller in diameter and start to change and act more and more like a non-metal.