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प्रश्न
An atom has electronic configurations 2, 8, 7.
What is the atomic number of this element?
उत्तर
The atomic number of this element is 17.
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संबंधित प्रश्न
Why do you think the noble gases are placed in a separate group?
What property do all elements in the same column of the Periodic Table as boron have in common?
The three elements predicted by Mendeleev from the gaps in his periodic table were known as eka-boron, eka-aluminimum and eka-silicon. What names were given to these elements when they were discovered later on?
What name were given by Mendeleev to the then undiscovered element germanium?
How do the properties of eka-aluminium element predicted by Mendeleev compare with the actual properties of gallium element?
Which group of elements was missing from Mendeleev's original periodic table?
In Mendeleev's periodic table, gaps were left for the elements to be discovered later on. An element which found a vacant place in the periodic table later on is:
(a) Be
(b) Si
(c) Ge
(d) Se
State the merits of Mendeleev's classification of elements.
Find the odd one out and give its explanation.
Match the columns.
| Column A | Column B |
| 1) Eka-aluminium | a) Scandium |
| 2) Eka-Silicon | b) Gallium |
| 3) Eka- boron | c) Germanium |
| d) Beryllium |
