Valence Electrons Group Properties 5 3 Valence Electrons

Valence Electrons �Elements in a group have similar properties because they have the same

Valence Electrons & Group Number When the A groups in the periodic table are

Alkali Metals �Group 1 A � 1 Valence Electron �Extremely Reactive and thus found

Alkaline Earth Metals �Group 2 A � 2 Valence Electrons �Highly Reactive Oyster shell

Boron Family �Group 3 A � 3 Valence Electrons �Ex: Aluminum = Most abundant

Carbon Family �Group 4 A � 4 Valence Electrons

Nitrogen Family �Group 5 A � 5 Valence Electrons �Elements with a wide range

Oxygen Family �Group 6 A � 6 Valence Electrons �Ex: Oxygen is the most

Halogens �Group 7 A � 7 Valence Electrons �Found as gas, liquid or solid

Noble Gases �He has 2 valence electrons �All the others have 8 �Colorless, odorless

Noble Gases �But, when electric current passes through noble gases, they emit different colors.

Electron Dot Diagram �When is an atom unlikely to react? �When the highest occupied

Electron Dot Diagram �The chemical properties of an element depend on the number of

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Valence Electrons & Group Properties 5. 3

Valence Electrons �Elements in a group have similar properties because they have the same number of valence electrons. �A valence electron is an electron that is in the highest occupied energy level of an atom.

Valence Electrons & Group Number When the A groups in the periodic table are numbered from 1 through 8, the group number matches the number of valence electrons in the electron configuration of an element in that group. • Valence electrons play a key role in chemical reactions. • Properties vary across a period because the number of valence electrons increases from left to right.

Alkali Metals �Group 1 A � 1 Valence Electron �Extremely Reactive and thus found only in nature as compounds

Alkaline Earth Metals �Group 2 A � 2 Valence Electrons �Highly Reactive Oyster shell with pearl Spinach plant Plaster cast

Boron Family �Group 3 A � 3 Valence Electrons �Ex: Aluminum = Most abundant metal in Earth’s Crust �Lab Glass materials

Carbon Family �Group 4 A � 4 Valence Electrons

Nitrogen Family �Group 5 A � 5 Valence Electrons �Elements with a wide range of physical properties �Used a lot in fertilizer

Oxygen Family �Group 6 A � 6 Valence Electrons �Ex: Oxygen is the most abundant element in the Earth’s crust

Halogens �Group 7 A � 7 Valence Electrons �Found as gas, liquid or solid �Despite these differences, chemical properties are the same

Noble Gases �He has 2 valence electrons �All the others have 8 �Colorless, odorless and extremely unreactive = STABLE

Noble Gases �But, when electric current passes through noble gases, they emit different colors. Helium emits pink, neon emits orange-red, argon emits lavender, krypton emits white, and xenon emits blue.

Electron Dot Diagram �When is an atom unlikely to react? �When the highest occupied energy level of an atom is filled with electrons, the atom is stable and not likely to react.

Electron Dot Diagram �The chemical properties of an element depend on the number of valence electrons. An electron dot diagram is a model of an atom in which each dot represents a valence electron. The symbol in the center represents the nucleus and all the other electrons in the atom.

Electron Dot Diagram