SPM Chemistry Form 4 Notes – Periodic Table of Elements (Part 3)

by BerryBerryTeacher

in Berry Reference (Notes)

Group 1 elements, also known as alkali metals are elements that can usually be remembered by students in the Periodic Table of Elements, simply due to its proximity to the left end of the table. (Most students read from left to right, obviously) The following notes in Berry Berry Easy is Part 3 of SPM Chemistry Form 4 Notes on Periodic Table of Elements. Similar to understanding noble gases (from Part 2), the trends for Group 1 elements in terms of electron arrangement of atoms, physical properties, chemical properties and specifically for this group, safety precautions will be discussed.

 

(Tips: Please follow the safety precaution prescribed by your teacher in handling the alkali metals (if you were given the chance to do so). The reason is simple, as you will only need to see the volatile nature of alkali metals here when they are in contact with water, Brainiac’s video on Alkali Metal <view here>. After viewing the video, you should have no reasons to not follow the safety precautions)

(Second Tips: Do try your best to memorise the elements down the group. Read aloud everyday a few times: Lithium, Sodium, Potassium, Rubidium, Caesium and Francium. If you do so, you’ll memorise it without much effort. That’ll be an advantage in exams.)

SPM Chemistry Form 4 Notes – Periodic Table of Elements (Part 3)

Alkali metal atom arrangement

Alkali metal atom arrangement

Group 1 elements

  • Group 1 elements are known as alkali metals
  • Atomic radius (atomic size) – increases (going down the group)
  • The outermost shell of the atoms (Li, Na, K, Rb, Cs and Fr) have 1 valence electron
  • Good reducing agents
  • Very reactive – increases (going down the group)
  • Very electropositive – increases (going down the group)
Element Electron arrangement of atom
Lithium / Li 2.1
Sodium / Na 2.8.1
Potassium / K 2.8.8.1
Rubidium / Rb 2.8.18.8.1
Caesium / Cs 2.8.18.18.8.1
Francium / Fr 2.8.18.32.18.8.1

Physical properties

  • Grey solids with shiny silvery surfaces when freshly cut
  • Soft solids at room temperature
  • Good conductors of electricity
  • Good conductors of heat
  • Low melting point and boiling point (compared to heavy metal)
  • Melting point and boiling point decreases (going down the group) – atomic size increases and number of shells occupied with electrons increases / metallic bonding between atoms becomes weaker & less heat energy is required to overcome the weaker metallic bonding.
  • Low density (Li, Na and K float on the surface water / Rb, Cs and Fr sink in the water)
  • Density of element increases (going down the group)

Chemical properties

  • Chemically very reactive and react rapidly with oxygen and water vapour in the air (must be kept in paraffin oil)
  • Reactivity increases (down the group) – how easily it can lose one (single) its valence electron to achieve stable (octet or duplet) electron arrangement
  • React vigorously with cold water – produce alkaline metal hydroxide solutions and hydrogen gas
  • React with oxygen – produce white solid metal oxides and metal oxides can dissolve in water to form alkaline metal hydroxide solutions
  • React with halogens – produce white solid metal halides

Safety precautions

  • Cannot hold with bare hands
  • Wear safety goggles and gloves
  • No flammable substance nearby
  • Avoid the fire

The next part, Part 4 in this series of notes from Berry Berry Easy on the Periodic Table of Elements for SPM Chemistry Form 4 students will be focused on Group 17 elements or Halogens such as Fluorine, Chlorine, Bromine, Iodine and Astatine. They are what the Berry Berry Teacher will call, the friendliest group of elements. After you learn this topic, you’ll understand why. :-)

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