Chemistry
State the number of elements in Period 1, Period 2, and Period 3 of the periodic table. Name them.
Answer
No. of elements in:
Period 1 = 2
Hydrogen (H) , Helium (He).
Period 2 = 8
Lithium (Li), Beryllium (Be), Boron (B), Carbon (C), Nitrogen (N), Oxygen (O), Fluorine (F), Neon(Ne).
Period 3 = 8
Sodium (Na), Magnesium (Mg), Aluminium (Al), Silicon (Si), Phosphorus (P), Sulphur (S), Chlorine (Cl), Argon (Ar).
Related Questions
In group I of the Periodic Table, three elements X, Y and Z have ionic radii 1.33 Å, 0.95 Å and 0.60 Å respectively. Giving a reason, arrange them in the order of increasing atomic numbers in the group.
Explain why are the following statements not correct:
(i) All groups contain metals and non-metals.
(ii) Atoms of elements in the same group have the same number of electron(s).
(iii) Non-metallic character decreases across a period with increase in atomic number.
(iv) Reactivity increases with atomic number in a group as well as in a period.
What is the common feature of the electronic configuration of the elements at the end of Period 2 and Period 3 ?
If an element is in Group 17, it is likely to be …………… [metallic/non-metallic] in character, while with one electron in its outermost energy level (shell), then it is likely to be …………… [metallic/non-metallic].