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romiroy12
romiroy12
@romiroy12
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Joined: Oct 18, 2020
Last seen: Jul 3, 2023
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Topics: 2049 / Replies: 0
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Topic
did Mendeleev have gaps in his periodic table? (b) any three limitations of Mendeleev’s classification. (c) does electronic configurations of atoms change in a period with increase in atomic number?
5 years ago
Forum
Periodic Classification Of Elements
Replies: 0
Views: 306
Topic
Which two criteria did Mendeleev use to classify the elements in his Periodic Table? (b) State Mendeleev’s periodic law. (c) Why could no fixed position be given to hydrogen in Mendeleev’s Periodic Table?
5 years ago
Forum
Periodic Classification Of Elements
Replies: 0
Views: 258
Topic
What are ‘groups’ and ‘periods’ in the ‘periodic table’? (b) Two elements M and N belong to groups I and II respectively and are in the same period of the periodic table. How do the following properties of M and N vary? 1. Sizes of their atoms
5 years ago
Forum
Periodic Classification Of Elements
Replies: 0
Views: 136
Topic
What is meant by periodicity in properties of elements with reference to the periodic table? (b) Why do all the elements of the same group have similar properties? (c) How will the tendency to gain electrons change as we go from left to right acros...
5 years ago
Forum
Periodic Classification Of Elements
Replies: 0
Views: 124
Topic
State Mendeleev’s periodic law. Write two achievements of Mendeleev’s periodic table.
5 years ago
Forum
Periodic Classification Of Elements
Replies: 0
Views: 195
Topic
Why was the system of classification of elements into triads not found suitable?
5 years ago
Forum
Periodic Classification Of Elements
Replies: 0
Views: 140
Topic
Chlorine, bromine and iodine form a Dobereiner’s triad. The atomic masses of chlorine and iodine are 35.5 and 126.9 respectively. Predict the atomic mass of bromine.
5 years ago
Forum
Periodic Classification Of Elements
Replies: 0
Views: 245
Topic
Lithium, sodium and potassium form a Dobereiner’s triad. The atomic masses of lithium and potassium are 7 and 39 respectively. Predict the atomic mass of sodium.
5 years ago
Forum
Periodic Classification Of Elements
Replies: 0
Views: 170
Topic
Why do we classify elements? (b) What were the two criteria used by Mendeleev in creating his Periodic Table? (c) Why did Mendeleev leave some gaps in his Periodic Table?
5 years ago
Forum
Periodic Classification Of Elements
Replies: 0
Views: 167
Topic
Table given below shows a part of the Periodic Table. H He Li Be B C N O F Ne Na Mg Al Si P S Cl Ar (b) Atomic size of Mg is less than that of Na. (c) Fluorine is more reactive than Chlorine.
5 years ago
Forum
Periodic Classification Of Elements
Replies: 0
Views: 779
Topic
What physical and chemical properties of elements were used by Mendeleev in creating his periodic table? List two observations which posed a challenge to Mendeleev’s Periodic Law.
5 years ago
Forum
Periodic Classification Of Elements
Replies: 0
Views: 249
Topic
The position of three elements A, B and C in the Periodic Table is shown below:Giving reasons, explain the following: (a) Element A is non-metal. (b) Atom of element C has a larger size than atom of element A.
5 years ago
Forum
Periodic Classification Of Elements
Replies: 0
Views: 315
Topic
The position of three elements A, B and C in the Periodic Table is shown below: Group 16 - Group 17
5 years ago
Forum
Periodic Classification Of Elements
Replies: 0
Views: 183
Topic
The elements of the third period of the Periodic Table are given below: Group - I - II - III - IV - V - VI - VII Period 3 - Na - Mg - Al - Si - P - S - Cl (a) Which atom is bigger, Na or Mg? Why? (b) Identify the most (i) metallic and (ii) ...
5 years ago
Forum
Periodic Classification Of Elements
Replies: 0
Views: 116
Topic
The elements of the second period of the Periodic Table are given below: Li Be B C N O F (a) Give reason to explain why atomic radii decrease from Li to F.
5 years ago
Forum
Periodic Classification Of Elements
Replies: 0
Views: 165
Topic
Fill in the blanks 1. Halogens belong to group ……… of the Periodic Table. 2. An element having electronic configuration (2, 8, 2) belongs to the ……… group.
5 years ago
Forum
Periodic Classification Of Elements
Replies: 0
Views: 150
Topic
Fill in the blanks 1. The concept of grouping elements into triads was given by ……… . 2. Mendeleev’s basis for the Periodic Table is ……… . 3. The basis for Modern Periodic Table is ……… .
5 years ago
Forum
Periodic Classification Of Elements
Replies: 0
Views: 344
Topic
H, Li, Na, K placed in group. Why?
5 years ago
Forum
Periodic Classification Of Elements
Replies: 0
Views: 155
Topic
An element has atomic number 17 to which group and period closer it belong.
5 years ago
Forum
Periodic Classification Of Elements
Replies: 0
Views: 112
Topic
“Fluorine is more electronegative than Iodine.” Give reason in support of this.
5 years ago
Forum
Periodic Classification Of Elements
Replies: 0
Views: 633
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