Presentation is loading. Please wait.

Presentation is loading. Please wait.

The Modern Periodic Table

Similar presentations

Presentation on theme: "The Modern Periodic Table"— Presentation transcript:

1 The Modern Periodic Table

2 Early Periodic Table – Atomic Number
In 1913 Henry Mosley discovered that each element contained a unique number of protons in the nuclei Arranged elements in order of atomic number. Resulted in a clear periodic pattern of properties.

3 Periodic Law There is a periodic repetition of chemical and physical properties of elements when arranged in increasing atomic number (increasing number of protons) called the periodic law

4 Representative Elements
Modern Periodic Table Organized in columns called groups or families Rows are called periods Group A – representative elements (1A-8A) Group B - transition elements (1B-8B) Representative Elements (Group A) Representative Elements (Group A) Transition Elements (Group B)

5 Classification of Elements
Three classifications for elements metals, nonmetals, and metalloids (semimetals).

6 Metals Properties of Metals shiny, smooth, solids (except mercury)
Good conductors of heat and electricity High densities High melting and boiling points Malleable – bended or pounded into sheets Ductile – drawn into wires

7 Groups of Metals Alkali metals – group 1A except H
Alkaline earth metals – group 2A Alkali metals and alkaline earth metals are chemically reactive Transition metals – group B elements Inner transition metals Lanthanide Actinide

8 Metals Alkali Metals Alkaline Earth Metals Transition Metals
(B group elements) Alkali Metals Alkaline Earth Metals Inner Transition Metals

9 Organizing by Electron Configuration
Group number for group A elements represents the number of valence electrons Atoms in the same group have similar chemical properties because they have the same number of valence electrons

10 Alkali Metals Electron configurations for alkali metals
Lithium 1s22s [He]2s1 Sodium s22s22p63s [Ne]3s1 Potassium 1s22s22p63s23p64s [Ar]4s1 Rubidium 1s22s22p63s23p64s23d104p65s1[Kr]5s1 What do the four configurations have in common? They have a single electron in their outermost energy level They all have one valence electron, thus similar chemical properties

11 Alkaline Earth Metals Electron configuration for alkaline earth metals
Beryllium [He]2s2 Magnesium [Ne]3s2 Calcium [Ar]4s2 Strontium [Kr]5s2 All alkaline earth metals have two valence electrons, thus similar chemical properties.

12 Question Time What are representative elements?
What are Group B elements called? What are the three classifications for elements? What are the characteristics of metals? Where are the alkali metals and alkaline earth metals located? Where are transition metals located? What are the inner transition metals? How many valence electrons do alkali metals and alkaline earth metals have?

13 Nonmetals Gases or brittle, dull looking solids
Poor conductors of heat and electricity Usually have lower densities, melting point, and boiling point than metals. Groups of nonmetals Halogens 7A Noble gases 8A sulfur

14 Nonmetals Noble Gases Halogens

15 Noble Gases Noble gases – Group 8A
Called inert gases because they rarely take part in a reaction He – 1s2 Ne – 1s22s22p6 Ar – 1s22s22p63s23p6 Kr - 1s22s22p63s23p63d104s24p6 Because noble gases have completely filled s and p sublevels, they do not react with other elements

16 Metalloids (Semimetals)
Physical and chemical properties similar to both metals and nonmetals They are metallic-looking brittle solids Relatively good electrical conductivity. Used in glasses, alloys, and semiconductors The six elements commonly recognized as metalloids are boron, silicon, germanium, arsenic, antimony, and tellurium. Polonium and astatine are sometimes classified as metalloids

17 Metalloids (Semimetals)

18 Question Time What are the properties of nonmetals?
Where are halogens and noble gases found? Why are noble gases unreactive (inert)? What are the properties of metalloids (semimetals)? Which six elements are most commonly known as metalloids (semimetals)?

Download ppt "The Modern Periodic Table"

Similar presentations

Ads by Google