Atomic Structure & The Periodic Table

Atomic Structure&The Periodic Table

The Structure of an atom

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• Bildunterschrift: Atomic Stricture
• Element- substance which contains only one type of atom.
• Atomic Number- The number of protons in the nucleus.
• Mass Number- Total number of protons and neutrons. (can be calculated by subtracting the atomic number from the mass number e.g mass number- atomic number=neutrons.
• Number of protons= Number of electrons
• Number of neutrons= mass number- proton number
• 59- Mass Number
• CO- Symbol for Element
• 27- Atomic number

Charges: Protons, Neutrons & Electrons

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• Bildunterschrift: Charges

Isotopes & Electronic Structure

• Isotopes- atoms that have the same number of protons but different number of neutrons.
• Atoms are more stable (less reactive) if they have a full outer shell of electrons. Only Atoms in group 8 e.g helium and neon have full outer shells of electron.
• Atoms in group 1 to 7 do not have a full outer shell of electrons so they want to fill their outer shell.
• From group 1-3 the shells lose electrons.
• In Group 4, the shells lose & gain electrons.
• From group 5-7 the shells gain electrons..
• Working out an elements electronic structure
• 1. Find the element in the periodic table,, work out what period it is in and draw that number of circles around the nucleus.
• 2. Work out which group the element is in and draw that number of electrons in the outer circle
• With 8 for group 0 elements
• 3. Fill the other circles with electrons (only two electrons in the first and 8 in the rest).
• 4. Finally count your electrons and check that they are equal to the atomic number.