c4.1 and c4.2

• What are the group 1 elements known as?

  Alkali metals
• Which elements are included in the alkali metals?

  Lithium, sodium, potassium, rubidium, cesium, and francium
• How do alkali metals differ from most other metals?

  They are relatively soft, have low densities, and low melting points
• What is the reactivity trend of alkali metals as you go down the group?

  The elements become more reactive
• Which alkali metal can ignite spontaneously at room temperature?

  Cesium
• What happens to the melting and boiling points of alkali metals as you go down the group?

  They decrease
• Why doesn't sodium catch fire when sprinkled on potatoes?

  Because it is in a stable ionic compound form as sodium chloride
• Why are alkali metals so reactive?

  They have one electron in their outermost shell that they can easily lose
• What charge do alkali metals become when they lose their outer electron?

  They become a one positive ion
• How does the atomic radius affect the reactivity of alkali metals?

  A larger atomic radius weakens the attractive force between the nucleus and the outer electron
• What is the definition of reactivity in terms of alkali metals?

  It relates to how easily atoms can lose or gain electrons
• What type of compounds do alkali metals typically form with non-metals?

  Ionic compounds
• What happens when sodium reacts with chlorine?

  Sodium donates an electron to chlorine, forming sodium chloride
• What is the appearance of ionic compounds formed by alkali metals?

  They are generally white solids
• How do ionic compounds behave in water?

  They tend to dissolve in water and form colorless solutions
• What do alkali metals produce when they react with water?

  A metal hydroxide and hydrogen gas
• What is the reaction equation for sodium reacting with water?

  $\text{Sodium} +$$\text{Water} \rightarrow \text{Sodium Hydroxide} +$$\text{Hydrogen}$
• How does the energy released in reactions change as you go down the group?

  More energy is released, especially from potassium onwards
• What do alkali metals form when they react with chlorine gas?

  White metal chloride salts
• What is the product of lithium reacting with oxygen?

  Lithium oxide
• What is the product of sodium reacting with oxygen?

  Sodium oxide
• What can sodium and oxygen also react to form besides sodium oxide?

  Sodium peroxide
• What can potassium react with oxygen to form?

  Potassium peroxide or potassium superoxide
• What are the general properties and trends of alkali metals?

  • Soft, low density, low melting points
  • Reactivity increases down the group
  • Melting and boiling points decrease down the group
  • Form ionic compounds with non-metals
• How do alkali metals react with water, chlorine, and oxygen?

  • React with water to produce metal hydroxide and hydrogen gas
  • React with chlorine to form white metal chloride salts
  • React with oxygen to form metal oxides
• What is the significance of ionic compounds formed by alkali metals?

  • Generally white solids
  • Tend to dissolve in water
  • Form colorless solutions
• What is the trend in energy release during reactions of alkali metals with water and chlorine as you go down the group?

  • More energy is released
  • Potassium onwards, reactions can ignite hydrogen gas
• What are the two groups of elements discussed in the video?

  Group seven elements (halogens) and group zero elements (noble gases)
• What are the properties of halogens?

  • Fluorine: poisonous yellow gas, very reactive
  • Chlorine: poisonous green gas, less reactive
  • Bromine: reddish-brown volatile liquid, poisonous
  • Iodine: dark gray solid, forms poisonous purple vapors, also an antiseptic
• What is the state of iodine at room temperature?

  Dark gray solid
• Why are astatine and tenocine generally ignored in the course?

  They don't really come up in the course
• What are diatomic molecules?

  They are molecules consisting of two atoms
• How do halogens form covalent bonds?

  By sharing electrons to form diatomic molecules
• What is an example of a compound formed by halogens and non-metals?

  Hydrogen fluoride
• What are the trends in properties of halogens as you go down the group?

  • Melting points and boiling points increase
  • Reactivity decreases
• Why does reactivity decrease as you go down the halogen group?

  The outermost shell gets further from the nucleus, weakening the attractive force
• What do we call a halogen that gains an electron?

  A halide
• What are the names of the halide ions formed from halogens?

  Fluoride, chloride, bromide, and iodide
• Which metals do halogens most often form ionic compounds with?

  Alkali metals in group 1
• What is a displacement reaction involving halogens?

  A more reactive halogen displaces a less reactive one