1.2.1 Arranging the Elements

Examples of Chemical Symbols:

O = Oxygen

Na = Sodium

C = Carbon

Ag = Silver

Au = Gold

W = Tungsten

Rules:

The first letter in a chemical symbol is always an UPPERCASE letter, and the other letters are always lowercase.

For example, the symbol for a magnesium atom is Mg and not mg, MG, or mG.

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The Periodic Table

All the different elements are arranged in a chart called the periodic table. A Russian scientist named Dmitri Mendeleev produced one of the first practical periodic tables in the 19th century. The modern periodic table is based closely on the ideas he used:

Key Concepts:

• The elements are arranged in order of increasing atomic number.
• The horizontal rows are called periods.
• The vertical columns are called groups.
• Elements in the same group have similar properties to each other.
• Metals appear on the left side of the table, while non-metals are on the right.

The Periodic Table

Structure of the Periodic Table:

• Periods: These are the horizontal rows (e.g., Period 1, Period 2, etc.).
• Groups: These are the vertical columns (e.g., Group 1, Group 2, etc.).
• Transitional Metals: These are found in the central block of the periodic table.
• Metals vs. Non-metals:
  • Metals are shaded in red.
  • Non-metals are shaded in yellow.

Intermediate Properties:

Elements that appear close to the divide between metals and non-metals often have intermediate properties. This means they can sometimes behave like metals and/or non-metals.