C1 Fundamental ideas

FUNDAMENTAL IDEAS

Atomic structure

• The nucleus of an atom is made of protons and neutrons.
• Protons have a positive charge, electrons a negative charge and neutrons not charged.
• The atomic number(or proton number) of an element is equal to number of protons in the nucleus of its atoms.
• Elements are arranged in order of their atomic numbers in the periodic table.
• The mass number is the sum of the protons and neutrons in the nucleus of an atom

The arrangement of electrons in atoms

• The atoms of the unreactive noble gases…