Choose the correct answer: In the periodic table alkali metals are placed in group - A:1, B:11, C:17, D:18 Which of the following properties: do not match with elements of the halogen family, A : They have seven electrons in their valence shell, B : They are highly reactive chemically, C: They are metallic in nature, D: They are diatomic in their molecular form.

Select the correct answer: The no. of electrons in the valence [outermost] shell of a halogen is A:1, B:3, C:5, D:7

The main group elements i.e. representative elements complete their electron configuration using s and p electrons in the periodic table. These elements range from the most metallic to the most non-metallic with intermediate properties, the semi-metals, in between .The elements which occur at the two extremes of the periodic table are highly reactive and therefore, these highly reactive elements do not occur in free state : they usually occur in the combined forms. Beryllium and aluminium exhibit many properties which are similar, but, the two elements differ in :

Which of the following statements concerning protium, deuterium and tritium is not true ? A)they are isotopes of each other B) they have similar electronic configurations C )they exist in the nature in the ratio 1 2 3 D) their atomic masses are in the ratio 1:2:3

Which of the following properties of IA group metals increases as the atomic number rises: (a) Metallic character (b) Ionic radius (c ) Melting point (d) Density (e ) Ionization potential Correct answer is:-

Tow elelments 'I' and 'Q' belong to the same periiod of the modern periodic table and are in Group-1 and Group-2 respectively. Compare their following characteristics in tabular from: (a) The number of electrons in their atoms (b) The sizes of their atoms (c) Their matallic characters (d) Their tendencies to loes electrons (e)The formula of their oxides (f) The fornula of their chlorides

Three elements A, B and C have 3,4 and 2 electrons respectively in their outermost shell. Give the group number to which they belong in the modern periodic table. Also, give their valencies.

(a) How is the valency of an element determined if its electronic configuration is known? Determine the valency of an element of atomic no. 9 (b) Given below are some elements of the Modern Periodic Table. Atomic numbers of the elements are given in the parentheses: A(4), B(9), C(14), D(19), E(20) (i) With the help of the electronic configuration, find out which one of the above elements will have one electron in its outermost shell? (ii) Which rwo elements belong to the same group? Give reasons for your answer. (iii) Which one of the above elements belonging to the fourth period has bigger atomic radius and why?.

Comprehension given below is followed by some multiple choice questions. Each question has one correct option. Choose the correct option. In the modern periodic table, elements are arranged in order of increasing atomic numbers which is related to the electronic configuration. Depending upon the type of orbitals receiving the last electron, the elements in the periodic table have been divided into four blocks, viz s, p, d and f. The modern periodic table consists of 7 periods and 18 groups. Each, period begins with the filling of a new energy shell. In accordance with the Aufbau principle, the seven periods (1 to 7) have 2, 8, 8, 18, 18, 32 and 32 elements respectively. The seventh period is still incomplete. To avoid the periodic table being too long, the two series of f-block elements, called lanthonoids and actinoids are placed at the bottom of the main body of the periodic table (iv) The electronic configuration of the element which is just above the element with atomic number 43 in th same group is ...........

Comprehension given below is followed by some multiple choice questions. Each question has one correct option. Choose the correct option. In the modern periodic table, elements are arranged in order of increasing atomic numbers which is related to the electronic configuration. Depending upon the type of orbitals receiving the last electron, the elements in the periodic table have been divided into four blocks, viz s, p, d and f. The modern periodic table consists of 7 periods and 18 groups. Each, period begins with the filling of a new energy shell. In accordance with the Aufbau principle, the seven periods (1 to 7) have 2, 8, 8, 18, 18, 32 and 32 elements respectively. The seventh period is still incomplete. To avoid the periodic table being too long, the two series of f-block elements, called lanthonoids and actinoids are placed at the bottom of the main body of the periodic table (ii) The last element of the p-block in 6th period is represented by the outermost electronic configuration.

Choose the correct answers: a. Which of the following alkali metal is the most electropositive ? i. Na , ii. K , iii. Rb , iv. Cs b. Which of the following alkali metals has the lowest m.pt. ? i. Li , ii. K , iii. Na , iv. Rb c. Which of the following is the stronger reducing agent ? i. Li , ii. Na , iii. K , iv Rb