Question

Answer the following

a) State modern periodic law.

b) Why group 1 elements are called

alkali metals?

c) How many elements are present

in the third period ?

d) What are 14 elements that come

after Lanthanum called?

e) What is the valency​

Answer 1

Answer:

a) modern periodic states that "The physical and chemical properties of the elements are periodic functions of their atomic numbers”.

b) The alkali metals are so called because reaction with water forms alkalies (i.e., strong bases capable of neutralizing acids).

c) The third period contains eight elements: sodium, magnesium, aluminium, silicon, phosphorus, sulfur, chlorine, and argon

d)The inner transition elements occupy a position in between the elements lanthanum (Z=57) and hafnium (Z=72), and between actinium (Z=89) and rutherfordium (Z=104). Elements 58-71, which follow lanthanum, are the lanthanides, and elements 90-103, which follow actinium, are the actinides.

e)a measurement of the power of an atom to combine with others, by the number of hydrogen atoms it can combine with or take the place of.

Answer 2

⭐Answer⭐

a) The mordern peeiodic law states "The chemical and physical properties of elements are a peeiodic function of their atomic numbers".

b) The alkali metals are so named because when they react with water they form alkalies. Alkalies are hydroxide compounds of these elements, such as sodium hydroxide and potassium hydroxide. ... Alkalies react with acids to form salts.

c) eight elements

d) The inner transition elements occupy a position in between the elements lanthanum (Z=57) and hafnium (Z=72), and between actinium (Z=89) and rutherfordium (Z=104). Elements 58-71, which follow lanthanum, are the lanthanides, and elements 90-103, which follow actinium, are the actinides.

e) In chemistry, the valence or valency of an element is the measure of its combining capacity with other atoms when it forms chemical compounds or molecules.

Hope it helps❤