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 choice that is not an indicator of a chemical change is "state of matter changes". more common than not, chemical reactions produce energy in the form of light or heat. along with energy, they also produce a new substance called the product that could be in any state of matter (solid, gas, or liquid)."

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.