Question

SAT2 化学题

which of the following radioactive processes when occurring separately ,must alter the atomic number of the radioactive nucleus?
1,alpha decay
2,beta decay
3,gamma decay
A,1
B,2
C,3
D,1,2
F,1,2,3
请解释一下为什么？

Answer 1

D
alpha decay: the nucleus loses 2 protons and 2 neutrons, so the atomic number is changed (reduced by 2).

beta decay: the most common form is that the nucleus loses an electron, so the the atomic number increases by 1.

Gamma decay: a nucleus changes from a higher energy state to a lower energy state through the emission of electromagnetic radiation (photons). The number of protons (and neutrons) in the nucleus does not change in this process, so the parent and daughter atoms are the same chemical element.

Answer 2

D. 1,2

alpha decay releases an alpha particle, which consists of two protons and two neutrons, therefore alpha decay will decrease the atomic number by two.

beta decay releases a beta particle, which is an electron, as a result of a neutron turning into a proton. threfore beta decay will increase the atomic number by one.

gamma decay releases a photon, and does not change atomic number.

Answer 3

翻译：下列哪种放射性过程发生时，一定会改变放射性核素的原子序数。1.2.3分别是阿尔法，贝塔，伽马衰变。从高中物理知识我们知道，只有发生阿尔法衰变时，才一定会改变原子序数。