Which of the following are True for α-decay.
i. mass number, decrease by four.
ii. Atomic number decreases by two.
iii. mass number does not change.
i and ii only
ii and iii only
i and iii only
i, ii, and iii only
Correct answer is A
No explanation has been provided for this answer.
114 days
814 days
30 days
80 days
Correct answer is C
half-life = 10 days
after 10 days, the 4g of element = 2g remaining with 2g disintegrated
after 10 days, 2g of element = 1g left with 1g disintegrated
hence, after 20 days, 3g of the element has been disintegrated with 1g left.
after 10 days, the 1g of element = 0.5g left with 0.5g disintegrated
after 30 days, we have 0.5g of element left with 3.5g disintegrated.
When an atom loses or gains a charge, it becomes
an electron
an ion
a neutron
a proton
Correct answer is B
No explanation has been provided for this answer.
Which of the following statements are TRUE of isotopes?
i. isotopes of an element have the same chemical properties because they have the same number of electrons.
ii. isotopes of elements are normally separated using physical properties.
iii. isotopes of an element have the same number of protons in their nuclei.
i and ii only
i and iii only
ii and iii only
i, ii, and iii
Correct answer is B
No explanation has been provided for this answer.