Advertisements
Advertisements
प्रश्न
An atom has the electron structure of 2, 7.
(a) What is the atomic number of this atom?
(b) To which of the following would it be chemically similar?
7N, 15P, 17Cl, 18Ar
(c) Why would you expect it to be similar?
उत्तर
(a) The atomic number of the atom is 9 (electronic configuration 2, 7), since it is the sum total of the electrons present in an atom.
(b) The atom would be chemically similar to 17Cl (electronic configuration 2,8,7).
(c) They are similar because both have the same number of valence electrons (7) in their atoms.
APPEARS IN
संबंधित प्रश्न
Rewrite the following statement after correction, if necessary:
Periods are the horizontal rows of elements.
The non-metal A is an important constituent of our food and most of the fuels around us. A forms two oxides B and C. The oxide B is poisonous whereas oxide C causes global warming.
(a) Identify A, B and C.
(b) To which group of periodic table does A belong?
(c) Name another element which is placed in the same group as A.
A non-metal X which is the largest constituent of air combines with hydrogen when heated in the presence of iron as catalyst to form a gas Y. When gas Y is treated with sulphuric acid, it forms a compound Z which is used as a chemical fertiliser.
(a) What are X, Y and Z?
(b) To which group of periodic table does X belong?
(c) Name the periodic table in which X is placed.
(d) Which element is placed just before X in the period?
(e) Which element is placed just after X in the period?
The elements Li, Na and K, each having one valence electron, are in period 2, 3 and 4 respectively of modern periodic table.
(i) In which group of the periodic table should they be ?
(ii) Which one of them is least reactive ?
(iii) Which one of them has the largest atomic radius ? Give reason in justify your answer in each case.
Alkaline earth metals have valency 2. This means that their position in the modern periodic table is in ______.
Answer the following question.
Write the name, symbol, and electronic configuration of an element X whose atomic number is 11.
Give a reason why elements need to be properly classified.
Example for liquid metal is ______.
Arrange the following elements in the order of their decreasing metallic character
Na, Si, Cl, Mg, Al
Which of the following metals have low melting and boiling point?
