11. Which of the following statements about isotopes is correct ?

A. Isotopes with odd atomic number are abundant
B. Isotopes with odd atomic number and even mass number are abundant
C. Isotopes with even atomic number and even mass number are abundant
D. Isotopes with even atomic number and odd mass no are abundant

12. One mole of CO2 contains?

A. 6.022 x 1023 atoms of oxygen
B. 22-gram electrons
C. 6.022 x 1023 atms of carbon
D. both B. & C.

13. The number of isotopes of elements with even mass number and even atomic number are ________________?

A. 280
B. 300
C. 154
D. 54

14. Which of the following terms is not used for ionic compound ?

A. formula unit
B. empirical formula
C. molecular formula
D. formula mass

15. moles of each aluminum and oxygen react with each other to produce aluminum oxide. The amount of product formed is______________________?

A. 0.18 mole
B. 0.27 mole
C. 0.24 mole
D. 0.09 mole

16. Which one of the following has the maximum number of isotopes ?

A. oxygen
B. carbon
C. tin
D. chlorine

19. Mass spectrometer is used to determine Mass number of isotopes and___________________?

A. Atomic number
B. Relative abundance
C. Electronic configuration
D. All of the above

20. The number of peaks obtained in mass spectrometer shows____________________?

A. Relative abundance
B. Average mass of element
C. Number of isotopes
D. Relative isotopic mass

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