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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
How could the Modern Periodic Table remove various anomalies of Mendeleev’s Periodic Table?
What was the Mendeleev's basis for the classification of elements?
State the periodic law on which Mendeleev's periodic table table was based. Why and how was this periodic law changed?
Besides gallium, which two other elements have since been discovered for which Mendeleev had left gaps in his periodic table?
Mendeleev predicted the existence of certain elements not known at that time and named two of them as eka-aluminium, and eka-silicon.
(a) Name the element which has taken the place of (i) eka-aluminium, and (ii) eka-silicon
(b) Mention the period/periods of these elements in the modern periodic table.
(c) Write the group/ groups of these elements in the modern periodic table.
(d) Classify these elements as metals, non-metals or metalloids.
(e) How many valence electrons are present in the atoms of each of these elements?
The correct formula of the oxide of Eka-aluminium element predicted by Mendeleev was:
(a) EaO3
(b) Ea3O2
(c) Ea2O3
(d) EaO
Write the name.
The family of group 1 elements.
Write the name.
The family of elements having zero valency.
Write scientific reason.
In a group, the size of the atom increases as it goes down from the top.
Which one of the following does not increase while moving down the group of the periodic table?
