SS2: CHEMISTRY - 1ST TERM
-
Periodicity and Periodic Table I | Week 15 Topics|1 Quiz
-
Quantum Numbers Orbitals & Electrical Structure | Week 26 Topics|1 Quiz
-
Periodicity and Periodic Table II | Week 312 Topics|1 Quiz
-
Periodic Table and Atomic Properties
-
Melting and Boiling Point
-
Electrical and Thermal Conductivities
-
Atomic Size [Radius]
-
Ionic Size [Radius]
-
Atomic Volume
-
Ionization Energy
-
Electron Affinity
-
Electronegativity
-
Differences between Ionization Energy and Electron Affinity
-
Summary of Trends of Atomic Properties
-
Theory Questions - Periodicity and Periodic Table II
-
Periodic Table and Atomic Properties
-
Periodicity and Periodic Properties III | Week 411 Topics|1 Quiz
-
Periodicity and Periodic Properties IV | Week 55 Topics|1 Quiz
-
Mass-Volume Relationship in Reaction | Week 68 Topics|1 Quiz
-
Types of Reactions: Oxidation and Reduction | Week 7 & 87 Topics|1 Quiz
-
Oxidation – Reduction Reaction II | Week 93 Topics|1 Quiz
-
Electrode Potential and Electrochemical Cells I | Week 106 Topics|1 Quiz
-
Electrode Potential and Electrochemical Cells II | Week 115 Topics|1 Quiz
-
Electrolysis I | Week 128 Topics|1 Quiz
-
Electrolysis II | Week 138 Topics|1 Quiz
Group II Elements
Topic Content:
- Group II Elements
Beryllium – 4Be → 2, 2
Magnesium – 12Mg → 2, 8, 2
Calcium – 20Ca → 2, 8, 8, 2
Group II elements include beryllium, magnesium, calcium, strontium, barium, and radium. Group II elements constitute the second most reactive group of metals. They are alkaline earth metals. They are divalent elementsAn atom, with a valency of two, which thus can form two covalent bonds is called divalent. For example, oxygen (O), magnesium (Mg), etc. have a valency of two. More.
Mg → Mg2+ + 2e–
Ca → Ca2+ + 2e-
They are electron donors and form electrovalent compoundsAn electrovalent or ionic bond is formed when a metal atom transfers one or more electrons to a non-metal atom. Ionic or electrovalent compounds are those compounds which are formed by... More. They are strong reducing agents. They are also good conductors of electricity.
Magnesium reacts with steam to liberate hydrogen and form magnesium oxide.
Mg[s] + H2O[g] → MgO[s] + H2[g]
Calcium reacts slowly with cold water to liberate hydrogen and form hydroxide
Ca[s] + 2H2O[l] → Ca[OH]2[aq] + H2[g]
Magnesium oxide is insoluble in water. But calcium oxide dissolves sparingly in water to form a calcium hydroxide solution.
CaO[s] + H2O[l] → Ca[OH]2[aq]
Their trioxonitrate[V] salts decompose on heating to give oxides, oxygen, and nitrogen[IV] oxide gas
\( \scriptsize 2Mg(NO_{3})_{2(s)} \overset{heat}{\rightarrow} 2MgO_{(s)} + O_{2(g)} + 4NO_{2(g)}\)Their trioxocarbonates [IV] decompose on heating to give the oxides and carbon[IV] oxide. They are insoluble in water.
\( \scriptsize MgCO_{3(s)} \overset{heat}{\rightarrow} MgO_{(s)} + CO_{2(g)} \) \( \scriptsize CaCO_{3(s)} \overset{heat}{\rightarrow} CaO_{(s)} + CO_{2(s)} \)