Advertisements
Advertisements
Question
Write a scientific reason.
There was ambiguity about the correct position of hydrogen in Mendeleev’s periodic table.
Advertisements
Solution
- Hydrogen resembles alkali metals. It has one electron in its outermost shell like alkali metals. Its valency is 1 like alkali metals. It forms oxides (H2O) similar to alkali metals (Na2O). However, hydrogen also resembles halogens. It is a diatomic molecule (H2) like halogens (F2, Cl2). It is one electron deficient to achieve stable electronic configuration similar to halogens.
- Due to this unique behaviour of hydrogen, it could not be decided whether the correct position of hydrogen is in the group of alkali metals or in the group of halogens.
Thus, there was ambiguity about the correct position of hydrogen in Mendeleev's periodic table.
APPEARS IN
RELATED QUESTIONS
Fill in the blank:
The modern periodic table consists of ……………. periods.
Nitrogen (atomic number 7) and phosphorus (atomic number 15) belong to group 15 of the Periodic Table. Write the electronic configuration of these two elements. Which of these will be more electronegative? Why?
What is meant by a period, in a periodic table?
Is it possible to have an element having atomic number 1.5 placed between hydrogen and helium?
The modern periodic table was prepared by ______.
Which element has two shells, both of which are completely filled with electrons?
Which element has the electronic configuration 2, 8, 2?
State how the valency of elements varies in a group of the periodic table?
On the basis of electronic configuration, how will you identify chemically similar elements?
Explain why, the first period of the periodic table has only two elements whereas second period has eight elements
What are the groups in a periodic table? Give two characteristics of each.
The following diagram shows a part of the periodic table in which the elements are arranged according to their atomic numbers. (The letters given here not the chemical symbols of the elements):
| a 3 |
b 4 |
c 5 |
d 6 |
e 7 |
f 8 |
g 9 |
h 10 |
|
| i 11 |
j 12 |
k 13 |
l 14 |
m 15 |
n 16 |
o 17 |
p 18 |
(i) Which element has a bigger atom, a or f?
(ii) Which element has a higher valency, k or o?
(iii) Which element is more metallic i or k?
(iv) Which element is more non-metallic, d or g?
(v) Select a latter which represents a metal of valency 2.
(vi) Select a letter which represents a non-metal of valency 2.
Consider the following elements:
20Ca, 8O, 18Ar, 16S, 4Be, 2He
Which of the above elements would you expect to be:
(i) very stable?
(ii) in group 2 of the periodic table?
(iii) in group 16 of the periodic table?
Name the metals in the first twenty elements.
Name the type of elements which have one electron short of octet.
Answer the following in respect of element `31/15 P `
To which group and period does it belong?
Fill in the blank:
The horizontal rows in the periodic table are called _____________.
The electronic configuration of an element T is 2, 8, 8, 1.
What is the group number of T?
What is meant in the periodic table by a period?
From the standpoint of atomic structure, what determines which elements will be the first and which the last in a period of the periodic table?
Define the atomic size.
Give the symbol and valency of the following element and radical.
Potassium
Give the symbol and valency of the following element and radical.
Sodium
Give the chemical formula of magnesium nitrate
Give the chemical formula of calcium phosphate
Name the following:
The group of the Modern Periodic Table to which calcium [Ca2+] belongs.
State the number of elements in Period 2 of the Periodic Table.
Find the odd one out and give its explanation.
Write a scientific reason.
Lithium and sodium are included in the same group in the periodic table.
Distinguish between:
s-block - p-block
The inert gas which lies in the third period is ______
Which of the following elements would lose an electron easily?
“Hydrogen occupies a unique position in Modern Periodic Table”. Justify the statement.
Compare the radii of two species X and Y. Give reasons for your answer.
- X has 12 protons and 12 electrons
- Y has 12 protons and 10 electrons
Choose an element from period 3 of modern periodic table that matches the description given below in instance. Give a reason for your choice.
It has a similar structure to diamond.
Choose an element from period 3 of modern periodic table that matches the description given below in instance. Give a reason for your choice.
It has same valency as Lithium.
The maximum number of electrons that can be accommodated in s, p,d, and f subshells are ______.
State the group and period, of the element having three shells with three electrons in valence shell.
Answer the following in respect of element \[\ce{_16^32S}\].
Give its formula with hydrogen.
