Download Chapter 4- The Periodic Table Section 1

 Chapter 4- The Periodic Table

Section 1- How Are Elements Organized

Periodic Law- repeating physical and chemical properties of element change periodically
with their atomic number

Valence Election- found on the outer most shell determines atoms chemical properties

Group- vertical column of elements in periodic table elements in group, have some of the
same chemical properties

Period- horizontal row of elements on a periodic table

John Newland noticed a periodic pattern, Dmitri Mendeleev invented the first periodic
table and Henry Moseley found a different physical basis for the arrangement of elements

Section 2- Tour Of The Periodic Table

Main Group Elements- elements in the s- block or the p- block of the periodic table

Alkali metal- one of the elements of group 1 of the periodic table

Alkaline- earth metals- one of the elements of group 2 of the periodic table

Halogen- one of the elements of group 17 of the periodic table

Noble gas- an unreactive element in group 18 of the periodic table

Hydrogen is the most common element in the world

Most of the elements are metals

Metals have great electricity

Transition metals- one of the metals that can use the inner shell before using the outer
shell in a bond

Metals can be mixed with one or more other elements usually other metals, to make an
alloy

The melting points of metals are very different

Section 3- Trends In The Periodic Table

The arrangements of the periodic table reveals trends in the properties of the element

Chemical Reactivity with water increases from top to bottom for group 1 elements

Ionization Energy is the energy required to remove an electron from an atom or an ion

Electron Shielding- the reduction of the attractive force between a positively charged
nucleus and its outermost electrons due to the cancellation of some of the positive charge
by the negative charges of the inner electrons

Ionization energy increases as you move across a period.

Bond Radius- half the distance from center to center of two like atoms that are bonded
together.

Atomic Radius decreases as you move down a group

Atomic Radius decreases as you move across a period

Electro negativity- measure of the ability of an atom in a chemical compound to attract
electrons

Electro negativity decreases as you move down a group.

Electro negativity increases as you move across a period.

Section 4- Where Did The Elements Come From

Most of the atoms in living things come from just six elements; carbon, hydrogen,
oxygen, nitrogen, phosphorus, and sulfur.

Nuclear Reaction- a reaction that affects the nucleus of an atom

Super Heavy Element- element whose atomic number is greater than 106

The 93 natural elements were formed by stars

A transition is a nuclear reaction in which one nucleus is changed into another nucleus.