Transcript Periodic Trends

Periodic Trends
Chapter 5
Part 2
Atomic Radius

The definition of the
radius of an atom is
90 % of the electron
density.
Atomic Radius

The radius of the
atom decreases
with each
increase in the
atomic number.
 Why?
 The pull of the
increased atomic
number attracts
the electrons
closer to the
nucleus.
Ionization Energy

The ionization energy
is the amount of
energy it takes to
detach one electron
from a neutral atom.
Electron Affinity

The energy change
with the addition of an
electron.
Electronegativity
Summary
Groups and Periods

We learned about
groups, the columns,
and periods, the rows.
 Now we will examine
the trends seen in
each group.
Group IA: Alkali Metals

Known as Alkali
Metals
 Very reactive
 Never found free in
nature
 React readily with
water
Group IIA: Alkaline Earth Metals

Known as Alkaline
earth elements
 All are metals
 Occur only in
compounds in nature.
Group IIIA
 Metalloids
 Includes Aluminum
 (the
most abundant metal in the earth)
Group IVA
 Includes
metals and nonmetals
 Go from nonmetals at the top of the
column to metals at the bottom
Group VA
Group VIIA: Halogens

As a group, the most
electronegative.
 Gains one electron to
have a noble gas like
electron configuration.
 Called halogens,
which mean "salt
forming"
 Are all highly reactive
Group VIIIA: Noble Gases

Least reactive group
 All elements are
gases
 Not very abundant on
earth
 Given the name noble
gas because they are
not very reactive
Metalloids

Elements that touch
the stair case have
both metal and non
metal characteristics.
 They are called semimetals or metalloids.
Transitional Metals

These elements
have valence
electrons in the d
orbital.