chemistry

• 4

  2He. What radiation is this

  Alpha
• 0

  -1 e. What radiation Is this

  Beta
• 4 ways to increase the rate of a reaction

  Add a catalyst, increase concentraion, increase surface/decrease particle size, increase temperature
• What are catalysts?


  A substance that speeds up the rate of a reaction but can be recovered and remains unchanged
• What are elements in the periodic table in order by

  Number of protons/ atomic number
• Elements in the same group have the same amount of

  Outer electrons , indicated by the group number
• What is in the nucleus of an atom?

  protons and neutrons
• Where are the electrons in the atom

  Outside the nucleus, on the outer shells.
• What do elements in the same group contain the same

  Valency and similar chemical properties
• Mass and charge of a proton

  Mass = 1 charge = +1
• Mass and charge of a neutron

  Mass = 1, charge = 0
• Mass and charge of an electron

  Mass = 0, charge = -1
• How is an atom neutral?

  same number of protons and electrons
• The mass number =?

  protons + neutrons
• Isotopes are


  Atoms with the same atomic number but different mass number / same number of protons different number of neutrons.
• What does covalent bonds form between

  Non metals
• A covalent bond is formed when

  2 positive nuclei are held together by their common attraction for a shared pair of electrons.
• What are the 7 diatomic elements

  Hydrogen, Nitrogen, Fluorine, Oxygen, Iodine, Chlorine, Bromine
• The shape of a covalent bond depends on the?

  Number of bonds and the orientation of the bonds
• The covalent bond shapes are

  Linear, angular, trigonal pyramidal, tetrahedral
• Covalent substances form either


  Covalent molecular or covalent network
• Features of a covalent molecular substance


  Have string covalent bonds within the molecules and weak attraction between the molecules, have low melting and boiling points, weak forces of attraction between molecules are broken when the substance changes state, do not conduct electricity
• Covalent molecular substance may dissolve in

  Other solvents
• Features of a covalent network substance

  Have a network of strong covalent bonds within a giant structure, have very high melting and boiling points because the strong covalent bonds are not easily broken, do not dissolve
• Do covalent network substances conduct electricity

  No because they don't have charged particles which are free to move
• When are ions formed?

  When atoms lose or gain electrons to obtain the stable electrons arrangement of a noble gas
• In general how does metal atoms and non-metals form ions

  Metals in general lose electrons forming positive ions, non-metals gain electrons forming negative ions
• What does ion-electrons equations show

  The formation of ions through loss or gain of electrons
• Ionic bonds are


  The electrostatic attraction between positive and negative ions
• Ionic compounds form


  Lattice structures of oppositely charged ions with each positive ion surrounded by negative ions and each negative ion surrounded by positive ions
• ionic compounds have


  Have high melting and boiling points because strong ionic bonds must be broken in order to break up the lattice
• Ionic compounds are or aren't soluble in water and why


  Many ionic compounds are soluble in water, as they dissolve the lattice structure breaks up allowing water molecules to surround the separated ions
• Do ionic compounds conduct electricity

  Ionic compounds conduct electricity only when molten or in solution as the lattice structure breaks up allowing the ions to be free to move.
• Explain the conduction of ionic compounds

  The movement of ions towards oppositely charged electrodes
• The ending -ide on a compound indicates


  That the compound contains the 2 elements indicated
• The ending -ite or -ate indicates


  That oxygen is also present
• What do you need to write the chemical formula

  Valency rules(1,2,3,4,3,2,1) and a periodic table
• In a compound what does the Roman numerals indicate

  The valency
• What can prefixes be used to determine

  The chemical formula
• The chemical formula of a covalent molecular substance gives?

  The number of each type of atom present in a molecule