Q. Which element has:
(a) two shells, both of which are completely filled with electrons?
(b) the electronic configuration 2, 8, 2?
(c) a total of three shells, with four electrons in its valence shell?
(d) a total of two shells, with three electrons in its valence shell?
(e) twice as many electrons in its second shell as in its first shell?

Q. An atom has electronic configuration $2,8,7$.
(a) What is the atomic number of this element?
(b) To which of the following elements would it be chemically similar?(Atomic numbers are given in parentheses.)?
$N\left(7\right)$ $F\left(9\right)$ $P\left(15\right)$ $Ar\left(18\right)$

Q. Element $X$ forms a chloride with the formula $XC{l}_2$, which is a solid with a high melting point. $X$ would most likely be in the same group of the Periodic Table as:

1. $Na$
2. $Mg$
3. $Al$
4. $Si$

Q. The position of three elements A, B and C in the Periodic Table are shown below-

Group $16$	Group$17$
-	-
-	A
-	-
B	C

(a) State whether A is a metal or non-metal.
(b) State whether C is more reactive or less reactive than A.
(c) Will C be larger or smaller in size than B?
(d) Which type of ion, cation or anion, will be formed by element A?

Q. How does the electronic configuration of an atom relate to its position in the Modern Periodic Table?

Q. (a) What property do all elements in the same column of the Periodic Table as boron have in common?
(b) What property do all elements in the same column of the Periodic Table as fluorine have in common?

Q. Which of the following statements is NOT a correct statement about the trends when going from left to right across the period of Periodic Table?

1. The elements become less metallic in nature.
2. The number of valence electrons increases.
3. The elements can lose their electrons more easily.
4. The oxides become more acidic.

Q. In the Modern Periodic Table, calcium (atomic number $20$) is surrounded by elements with atomic numbers $12,19,21$ and $38$. Which of these have physical and chemical properties resembling calcium?

Q. Nitrogen (atomic number $7$) and phosphorus (atomic number $15$) belong to the group $15$ of the Periodic Table. Write the electronic configuration of these two elements. Which of these will be more electronegative and Why?

Q. Compare and contrast the arrangement of elements in Mendeleev's periodic table and the Modern periodic table.