biochemistry

• the building unit of the matter is the atom
• the atom consists of 2 main parts the nucelus and the energy levels
• the sub particles of the atom are the electrons, protons and neutrons
• the protons are the positively charged particles in the nucleus of an atom
• the electrons are the negatve charge particles in an atom
• the neutrons are neutrally charged
• the atom is neutrally charged (has no charge, electrically neutral) because it has an equal number of protons and electrons
• the atomic number=number of protons
• the atomic number doesn't change
• each element has a special atomic number
• the mass number= number of protons + number of neutrons
• number of neutrons = mass number - atomic number
• Isotopes are atoms of the same element with different numbers of neutrons.
• chemical compound: a substance made up of two or more different elements chemically combined
• Ionic bonding: A bonding type in which oppositely charged ions are attracted to each other.
• Ionic bonding happens between a positive ion and a negative ion. The bond is formed when the electrons are transferred from one atom to the other.
• the positive ion is the one that gains an electron and is called the anion
• the positive ion is the one that loses an electron and called a cation
• pure element: consists of one type of atom
• chemical compound: consists of 2 or more different elements chemically combined
• chemical mixture: consists of 2 or more substances that are physically mixed together but not chemically combined
• single bond consists of

  one pair of electrons
• single bond consists of: one pair of electrons (2 electrons)
• double bond consists of: two pairs of electrons (4 electrons)
• triple bond consists of: 3 pairs of electrons (6 electrons)
• Ionic bonding is based on transferring electrons from one atom to another.
• Covalent bonds form when atoms share electrons.