When an alpha particle is emitted from the nucleus of an atom?

During an alpha decay

Explanation:

An alpha particle is a particle consisting of 2 protons and 2 neutrons - basically it is equivalent to a nucleus of helium.

Alpha particles are emitted during alpha decays, which are one of the three types of radioactive decays (the other two being beta decay and gamma decay) in which an unstable nucleus decays emitting an alpha particle:

In the process, the original nucleus X loses 2 protons and 2 neutrons, so:

- its atomic number decreases by 2 units: Z --> Z-2

- its mass number decreases by 4 units: A --> A-4

cell differentiation  is how generic embryonic  cells  become specialized  cells. this occurs  through a process called gene expression. gene expression is the specific combination of genes that are turned on or off (expressed or repressed), and this is what dictates how a  cell  functions.

explanation:

inverse v=i*r

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