Elements are arranged by atomic number Vertically into Groups Horizontally Into Periods
Draw electron configuration diagrams to show the electronarrangements for these elements on the periodic table provided remember 2,8,8,2 Do this for the first twenty elements before the next slide.
Make a conclusion: Look at thediagrams you drew for each group . . . Each atom has the same number of electrons in it’s outermost shell. These electrons are called valence electrons. Valence electrons determine how an element will form chemical bonds and react.
For example - the Group 2 elements all have 2valence electrons. Be (Beryllium) Atom Mg (Magnesium) Atom
• The number of outer or “valence” electrons in an atom effects the way an atom bonds.• The way an atom bonds determines many properties of the element.• This is why elements within a group usually have similar chemical properties.For example alkali (group 1) metals allreact with water to produce hydrogen gas
If you looked at an atom from each element ina period What do you see… Each atom has the same number of electron holding shells.
For example: the period 4 atoms each have 4 electronshells 4 K (Potassium) Kr (Krypton) Atom Atom Fe (Iron) Atom
Now, use a different color and write the 2,8,8,2electron arrangements for the first 20 elements onyour handout. 1 2 2,1 2,2 2,3 2,4 2,5 2,6 2,7 2,8 2,8,1 2,8,2 2,8,3 2,8,4 2,8,5 2,8,6 2,8,7 2,8,8 What do you observe? 2,8,8,1 2,8,8,2 The last number in the electron arrangement indicates the number of valence electrons. This is the same for all elements in a group.
Other useful things to knowabout the Periodic Table
Solids, liquids and gases(at room temperature)