Answer:
a) The ionization energy of Be is larger than Mg. Be > Mg:
The ionization energy is the energy required to remove an electron from a gaseous atom or ion. Be has a higher ionization energy than Mg because Be has a smaller atomic radius and stronger nuclear charge than Mg. This means that the outermost electrons in Be are held more tightly by the nucleus and are harder to remove than the outermost electrons in Mg.
b) Alkali metals impart characteristic color to the flame:
When alkali metals are heated in a flame, they emit light of a characteristic color. This is due to the excitation of electrons in the outermost energy level of the metal atoms. As these excited electrons return to their ground state, they release energy in the form of light. The wavelength and color of the emitted light are characteristic of each element and can be used to identify the presence of alkali metals in a sample.
c) It is difficult to remove the second valence electron than the first electron in the elements of group IA:
The elements of group IA (also called alkali metals) have one valence electron in their outermost energy level, which is relatively far from the nucleus and therefore weakly held. As a result, it is relatively easy to remove the first valence electron and form a cation. However, removing a second valence electron requires overcoming a much stronger electrostatic attraction between the remaining positive ion and the negatively charged electron. Therefore, it is more difficult to remove the second valence electron than the first electron in the elements of group IA.
d) Quick lime produces hissing sound when added into cold water:
Quicklime, also known as calcium oxide (CaO), reacts with water to form calcium hydroxide [Ca(OH)2]. This reaction is highly exothermic and releases a large amount of heat, which causes the water to boil rapidly and steam to escape from the solution. The escaping steam causes the hissing sound.
Step-by-step explanation: