The nuclei of atoms also contain neutrons, which help hold the nucleus together. ... The total weight of an atom is called the atomic weight. It is approximately equal to the number of protons and neutrons, with a little extra added by the electrons.
The mass of a given atom, measured on a scale in which the hydrogen atom has the weight of one. Because most of the mass in an atom is in the nucleus, and each proton and neutron has an atomic weight near one, the atomic weight is very nearly equal to the number of protons and neutrons in the nucleus.
Answer: A decomposition reaction occurs when one reactant breaks down into two or more products.
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Use equation
number of moles= sample mass/molar mass
... indicates that it also has a high concentration of Hydroxide (OH) and that it is more basic.
Answer: a. solution
Explanation:
A solution is a mixture which contains two or more than two types of components and they can be separated by physical means as well.Example: salt water
Molecule of an element is defined as the aggregate of atoms of similar elements. Example:
. Molecule of a compound is the aggregate of atoms of different elements in a fixed ratio by mass. Example: 
Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.It can be decomposed into simpler constituents using chemical reactions. Example: 
A pure substance is a substance which contains definite composition of only one type of component. Hence, it cannot be separated by physical means. Example: Helium, water