Chemistry

• Define an atom

  All elements are made up of very small particles called atoms.

  An atom is the smallest unit of matter.
• What is in the nucleus of an atom?


  Protons and neutrons
• How do you know how many protons are in the nucleus of an atom?


  It is the same as the atomic number
• What is found on the shell of an electron?


  Electrons
• Why is an atom neutrally charged?


  An atom has the same number of protons (positive) and electrons (negative). Meaning the positive and negative charges cancel each other out.
• What is the mass of a proton?


  1
• What is the mass of a neutron?


  1
• What is the mass of an electron?


  0
• Why do electrons need to be far apart?


  To avoid repulsion forces
• Why are electrons arranged in shells or energy levels?


  To help space out all the negative charges
• How many electrons can the first shell hold?

  up to 2 electrons
• How many electrons can the second shell hold?


  Up to 8 electrons because it is bigger and further away from the nucleus
• How many electrons can any shell after the second hold?


  8 electron
• What element is this atom from?


  Boron

  2,3

  
• What element is this atom from?

  Oxygen

  2,6

  
• What element is this atom from?

  Phosphorus

  2,8,5

  
• What is the octet rule?


  The octet rule states that atoms tend to gain, lose, or share electrons in order to achieve a stable electron configuration with eight electrons in its outer shell.
• The reactivity of an atom depends on...

  how many electrons it has in its outer shell. The closer an atom is to having a full puter shell the more reactive it will be.
• Elements of the same group have similar reactivity because...


  they have the same number of electrons in their outer shell.
• All group 1 elements have one outer electron which means...


  They are very reactive and will behave in a similar way.
• How do you calculate the mass number?


  Mass Number = number of protons + number of neutrons
• What is nuclide notation?


  35 = Mass Number

  17 = Atomic Number

  Cl = Atomic Symbol

  
• What is the mas number of chlorine?


  It depends
• What is an isotope?


  An isotope is a variant of an element that has the same number of protons but a different number of neutrons in its nucleus.
• Isotopes 


  Each of two or more forms of the same element has the same atomic number but different mass numbers. As atoms of the same element, they have identical chemical properties.
• For the octet rule atoms what to achieve a...


  full outer shell because it is the most stable electronic state the can have.
• Only electrons in the...


  outer shell can take place in bonding.
• What shell is represented in diagrams?


  Because we only need the outer shell electrons for bonding, only outer shell electrons are represented in diagrams.
• What elements does covalent bonding occur in?


  Nonmetal atoms
• What happens during covalent bonding?


  The two non-metal atoms share electrons in order to achieve a full outer shell. Shared electrons belong to both atoms equally.