CIE Chemistry Paper-1: Specimen Questions 56 - 58 of 99
Question number: 56
Three elements Chlorine, Bromine and iodine have similar properties and they form a Dobereiner’s triad. If the atomic mass of chlorine is 35.5 and that of iodine is 126.9. What will be the atomic mass of Bromine (approx. value)
According to Dobereiner’s triad
Atomic mass of Bromine = Average of atomic masses of Cl and I
Now, = Average of atomic masses of Cl and I =
Therefore 79.9 will be the atomic mass.
Question number: 57
Electron configuration of an element X is 1s22s22p63s23p64s23d3, which one of the following statements are true for X element.
i) Period number of X is 4 and it is transition element
ii) X is a non metal
iii) Valence electrons of X are in “s” and “d” shells.
ii) and iii)
i) and iii)
|d.||All of the above|
X element has electron configuration;
Period of the element is equal to highest energy level of electrons or principal quantum number.
Therefore, X is in period 4
The group to which it belong will be 3 + 2=5 B group. Therefore is a metal
Question number: 58
Which of the following is a type of decomposition reaction:
|d.||None of the above|
The reaction in which heat energy is given to the substance and substance breaks into two or more simpler substances is called thermal decomposition reaction.