quizlet

• What is the relative mas of an electron?

  0
• What is an isotope?

  Isotopes are different atomic forms of an element that have the same number of protons but different number of neutrons, therefore different mass numbers.
• What is the relative atomic mass?

  The average mass of all the isotopes of an element
• How to find relative atomic mass

  (mass of isotope A x % of isotope A) + (mass of isotope B x % of isotope B) / 100

  
• What is a element?


  A substance made up of only one type of atom
• What is a mixture?

  Two or more different substances which are NOT chemically combined together
• What is a molecule?

  a group of atoms held together by chemical bonds
• What is a compound?

  a substance made of two or more different elements which ARE chemically bonded together
• What is a pure substance?

  A single element or compound
• Is a mixture a pure substance?


  -NO, it will melt or boil gradually over a range of temperatures
• pure substance has a


  fixed melting and boiling point
• What are the physical properties of all group 1 alkali metals?


  -soft, malleable

  -low density

  -low melting points
• How does the reactivity of group 1 alkali metals compare to other groups?

  More reactive than other groups
• What trend do the melting and boiling points of group 1 alkali metals follow as you go down the group?

  Melting and boiling points decrease as you go down the group
• As you go down group 1, reactivity


  INCREASES!!

  
• Why does Group 1 become more reactive as you go down the group??


  The reactivity of group 1 elements increase as you go down the group because the atoms become larger which means that the outer electron becomes further from the nucleus. This means that the electrostatic attraction between the positive nucleus and the outer negative electron decreases in strength. Which means the outer electron will be lost more easily, and the element will be more reactive.
• alkali metals + water =


  metal hydroxide + hydrogen
• alkali metals + oxygen

  metal oxide
• Why are group 0 elements unreactive?

  Group 0 are unreactive because they have full outer shell, so they dont need to gain or lose any electrons
• What is an ion?


  An atom that lost/gained electrons, which is now a charged particle
• What is an ionic bond?


  An ionic bond is the strong electrostatic forces of attraction between oppositely charged ions

  
• What is an ionic compound?

  A compound that consists of positive and negative ions

  
• Why do elements in the same group have similar properties?


  they have the same number of electrons in their outer shell
• Why do ionic compounds have high melting and boiling points?


  Because of the strong electrostatic attraction between ions, it takes a lot of energy to overcome this attraction and break the many strong bonds.
• Why can ionic compounds conduct electricity when they are liquids or dissolved in water?

  Because the ions can now move and carry the charge

  
• Test for hydrogen


  a lighted splint 'pops

  
• Test for oxygen


  Relights a glowing splint

  
• Test for carbon dioxide


  Bubble through limewater, turns from colourless to cloudy

  
• Test for chlorine


  damp blue litmus paper turns white

  
• Test for ammonia


  Turns damp red litmus paper blue
• How to do a flame test

  1. Dip inoculating loop wire into hydrochloric acid

  2. Dip into solid sample

  3. Place in blue Bunsen flame

  
• What colour is Lithium, Li+ flame?

  Crimson red
• What colour is sodium,Na+ flame?

  Yellow
• What colour is Potassium,K+ flame?

  Lilac
• What colour is Calcium,Ca 2+ flame


  Orange-red
• What colour is copper,Cu2+ flame?

  blue-green
• Test for cations


  Add sodium hydroxide
• what colour is copper precipitate

  blue
• what colour is iron II, fe 2+ precipitate


  Sludgy green
• what colour is iron III, fe 3+ precipitate


  Reddish brown