Reading the Periodic Table

Objectives:• 1. Explain why elements in a group have similar

properties.• 2. Identify the four blocks of the periodic table.Key Terms:• Group, family, period, alkali metal, alkaline earth

metal, halogen, noble gas, metal, nonmetal, semimetal, valence electron, abbreviated electron configuration, noble gas inner core

The Periodic Table• Our current periodic table lists 114 elements. It is arranged according to

the periodic law: – Elements are arranged in order of increasing atomic number in rows called periods.– Elements that have similar properties are arranged in groups or families - vertical

columns

Groups & Families• 1 (1A) - alkali metals (1s1-7s1) • 2 (2A) - alkaline earth metals (1s2-7s2) • 17 (7A) - halogens (2p5-6p5) • 18 (8A) - noble gases (1s2,2p6-6p6) • Families are named after the top element… 14 (4A) - sometimes known as the

Carbon family • Elements also grouped into regions based on similar properties

– Transitional Metals (d-block)– Rare Earth Metals (f-block)

Similarities Based on Region– main group elements

• s-block is group 1 & 2 ( 1A & 2A) • p-block is group 13 through 18 ( 3A to 8A)

– transition metals • d-block is group 3 through 12 ( 3B to 2B numbers are not sequential)

– rare earth elements (inner transition metals) • f-block is located below the main table

Valence Electrons• Elements of the same group (column) have the same valence (bonding)

electrons – main group elements (s & p orbitals) – Valence electrons are equal to the group number

• Alkali metals 1 valence e-• Nobel gases 8 valence e-

– Valence electrons by period• 2 valence electrons in n = 1 • 8 valence electrons in n = 2 - n = 6 • 2 valence electrons in n = 7