Periods in Modern Periodic Table

Q.

How many elements are there which are in gaseous state at room temperature?

Q.

What is Group 13 on the periodic table called?

Q.

Name the following:

The lightest metal

Q.

What is the meaning of halogens?

Q. On moving from left to right in a period in the periodic table, the size of the atom.

1. Increases
2. Decreases
3. Does not change appreciably
4. First decreases and then increases

Q.

What is the difference between Transition and Inner transition elements?

Q. Atomic number is Phosphorus is 15
Electronic configuration=K L. M
2. 8. 5
To form octet it requires 3 electron .Hence valency should be 3 but why is valency of Phosphorus is 5 as well as 3 .??

Q. Question 3 (c)
Which element has a total of three shells, with four electrons in its valence shell?

Q. If by Neil's Bohr formula the no. Of electrons is 2n^2 . And if 3rd shell contains 18 electrons . Why did he said that the outermost shell can maximum hold 8 shells?

Q.

Why most active element in group 17 is Fluorine?

Q.

Properties of elements are the periodic function of their atomic number and not the atomic masses.

Q.

How do atomic structures (electron arrangements ) change in a period with increase in atomic numbers moving left to right ?

Q.

What do you mean by the atomicity of an element?

Q.

The modern periodic table contains ___________ groups.

Q.

What is meant in the periodic table by :

(a) a group, and

(b) a period ?

Q.

The number of electrons in the valence shell of phosphorus (Z = 15) is 5. True or False

1. True

2. False

Q.

Which element has two shells, both of which are completely filled with electrons?

1. Xenon

2. Neon

3. Argon

4. Lithium

Q. Be, Mg, Ca, Sr, Ba and Ra belong to group - ______ of the modern periodic table.

1. 8
2. 12
3. 15
4. 2

Q. Question 21
Will ${}_{35}Cl$ and ${}_{37}Cl$ have different valencies? Justify your answer.

Q.

In long form of periodic table, second period is the shortest period.

1. True
2. False

Q. Question 25
On moving from left to right in a period in the periodic table, the size of the atom.

(a) increases
(b) decreases
(c) does not change appreciably
(d) first decreases and then increases

Q.

Besides sulphur and chlorine, which other non-metallic element is present in the third period?

1. Oxygen
2. Fluorine
3. Phosphorus
4. Nitrogen

Q.

Horizontal rows in periodic table are called__________________

Q.

The number of atoms present in one molecule of an element is called-

Q. Which of the following element has a total of two shells, with three electrons in its valence shell?

1. Lithium
2. Boron
3. Phosphorus
4. Oxygen

Q. The number of shells and valence electrons for an element with atomic number 14 are ___ and ___.

1. 2, 4
2. 4, 4
3. 3, 4
4. 4, 3

Q.

(i) Electropositive nature of the element(s) increases down the group and decreases across the period
(ii) Electronegativity of the element decreases down the group and increases across the period
(iii) Atomic size increases down the group and decreases across a period (left to right)
(iv) Metallic character increases down the group and decreases across a period.
On the basis of the above trends of the Periodic Table, answer the following about the elements with atomic numbers 3 to 9.

Name the element which shows maximum valency.

1. Beryllium

2. Carbon

3. Nitrogen

4. Oxygen

Q.

(i) Electropositive nature of the element(s) increases down the group and decreases across the period
(ii) Electronegativity of the element decreases down the group and increases across the period
(iii) Atomic size increases down the group and decreases across a period (left to right)
(iv) Metallic character increases down the group and decreases across a period.
On the basis of the above trends of the Periodic Table, answer the following about the elements with atomic numbers 3 to 9.

Name the most electropositive element among them

1. Boron (B)

2. Carbon(C)

3. Lithium (Li)

4. Beryllium (Be)

Q.

here are how many elements in periodic table

Q. Which one of the following has the maximum metallic character?

1. Sodium
2. Magnesium
3. Aluminium
4. Silicon