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Question
Name the elements in Period 1.
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Solution
Names of elements are (H) Hydrogen and Helium (He).
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RELATED QUESTIONS
Two elements ‘A’ and ‘B’ belong to the 3rd period of Modern periodic table and are in group 2 and 13, respectively. Compare their following characteristics in tabular form:-
(a) Number of electrons in their atoms
(b) Size of their atoms
(c) Their tendencies to lose electrons
(d) The formula of their oxides
(e) Their metallic character
(f) The formula of their chlorides
How do the atomic size and metallic character of elements vary as we move :-
(a) down a group and
(b) from left to right in a period
List any two properties of the elements belonging to the first group of the modern periodic table.
The electrons in the atoms of four elements A, B, C and D are distributed in three shells having 1, 3, 5 and 7 electrons in the outermost shell respectively. State the period in which these elements can be placed in the modern periodic table. Write the electronic configuration of the atoms of A and D and the molecular formula of the compound formed when A and D combine.
Consider two elements 'X' (Atomic number 17) and 'Y' (Atomic number 20)
(i) Write the positions of these elements in the modern periodic table giving justification.
(ii) Write the formula of the compound formed by the combination of 'X' and 'Y'.
(iii) Draw the electron-dot structure of the compound formed and state the nature of the bond formed between the two elements ?
Which element has a total of three shells, with four electrons in its valence shell?
The atomic number of an element is 20. In modern periodic table, this element is placed:
(a) 2nd period
(b) 4th period
(c) 3rd period
(d) 1st period
Which of the following element does not lose an electron easily?
(a) Na
(b) F
(c) Mg
(d) Al
Complete the following sentences
The similarities in the properties of a group of elements are because they have the same …………………
State whether the following statement is true or false
On moving horizontally across a period, number of valence electrons increases from one to eight.
