elements and the periodic table

• Atom


  The smallest part of an element that can exist
• Element


  Substance made of only one type of atom, can be found on the Periodic Table
• Compound


  Substance made of two or more different types of atom chemically bonded together
• Chemical bond


  Force of attraction which holds two atoms together
• Molecule


  Two or more atoms chemically bonded together
• Group


  A column of elements on the periodic table, elements in the same groups have similar properties
• Period


  A row of elements on the periodic table
• Atomic number


  The number of protons in the nucleus of an element
• Atomic mass


  The number of protons + neutrons in the nucleus of an element
• Law of Conservation of Mass - no atoms are lost or made in a chemical reaction
• Trend in Group 1 Physical Properties

  • Going down the group: Melting point and boiling points decrease, Easier to cut- softer, All Group 1 elements are very reactive
• Trend in Group 1 Chemical Properties

  • Going down the group: Elements react more vigorously
• Trend in Group 7 Physical Properties

  • Going down the group: Melting point and boiling points increase, Colours of elements change, Relative Atomic Mass increase
• Group 7 Chemical Reactivity

  • Going down the group: Elements react less vigorously
• 4 neutrons, 3 protons, 3 electrons
• Hydrogen + Chlorine → Hydrogen chloride
• H₂ + Cl₂ →


  71g → 2g +
• Water H₂O
• 2HCI 738
• Carbon Dioxide CO₂
• The atomic number is equal to the number of protons.
• Isotopes are atoms with different numbers of neutrons but the same number of protons.
• Atoms are neutral, meaning they have an equal number of electrons and protons.
• Element


  A substance made up of only one type of atom, found on the Periodic Table
• Atom


  The basic unit of a chemical element, consisting of a dense nucleus containing protons and neutrons, surrounded by a cloud of electrons
• Type of atom


  Each atom is characterized by the number of protons in its nucleus, which is unique to that particular element</front> <front>Periodic Table</front> <back>A tabular arrangement of chemical elements, organized on the basis of their atomic number, electron configuration, and recurring chemical properties
• Substance


  A form of matter that has a distinct set of properties and can be separated from other materials