In an alpha particle, consisting of two neutrons and two protons, is emitted from the nucleus of an atom. the daughter element will have an atomic number 2 less than and an atomic mass 4 less than the parent element.

In alpha decay, an alpha particle is emitted.

Explanation:

Alpha decay is defined as the decay process where an alpha particle is emitted. In this process, a heavier nuclei decays into a lighter nuclei. The alpha particle emitted carries a charge of +2 units and a mass of 4 units.

The emitted alpha particle is also known as helium nucleus.

In this decay process, the atomic number of the parent atom decreases by 2 units and the mass number decreases by 4 units.

The chemical equation for alpha decay process follows:

Hence, in alpha decay, an alpha particle is emitted.

the mantle

explanation:

earth is divided into three layers: the crust or the outermost layer on which we live; the underlying, middle layer - the mantle - and the core (the innermost layer of earth).

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.