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TSR Wiki > Study Help > Subjects and Revision > Revision Notes > Chemistry > Some Reminders about the Periodic Table

• The elements are laid out in order of Atomic Number

• Hydrogen, 1, H, does not readily fit into any group

• A Group is a vertical column of like elements eg Group 1 The Alkali Metals (Li, Na, K etc.), Group 7 The Halogens (F, Cl, Br, I etc.) and Group 8 or 0 The Noble Gases (He, Ne, Ar etc.). The group number equals the number of electrons in the outer shell (eg chlorine's electron arrangement is 2.8.7, the second element down in Group 7).

• A Period is a horizontal row of elements with a variety of properties (more metallic to more non-metallic. All the elements use the same number of electron shells which equals the period number (eg sodium's electron arrangement 2.8.1, the first element in Period 3).

• On Period 4 is a horizontal row of ten elements between Group 2 and Group 3, Sc to Zn are called the first Transition Metals Series of Elements.

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