Atomic Number tells you how many protons and electrons there are in a neutral atom.
No two elements may have the same atomic number. But two elements may have same atomic mass. Hence atomic number is better than atomic mass.
There is no element with an atomic number of 12 and an atomic mass of 8. Atomic number corresponds to the number of protons in an atom, while atomic mass is the sum of protons and neutrons. The atomic number of an element cannot be smaller than its atomic mass.
The Atomic Number of an element is the number of Protons in its nucleus, that is what determines what element the atom is. The Atomic Mass is the total mass of Protons, Neutrons, and (negligable) Electrons, but that means the Atomic Mass will be larger than the Atomic Number.
Yes
The atomic mass of iodine is about 126.9 g/mol, which is indeed less than the atomic mass of many other elements. This low atomic mass for iodine is due to its position in the periodic table and the number of protons and neutrons in its nucleus.
Mass number minus the atomic number equals the number of neutrons. Mass number is the number of particles in an atom that have significant mass. Electrons are assigned a value of 0 since the mass is so much smaller than protons and neutrons. Protons and neutrons are similar in mass and are assigned mass number of 1. The formula for calculating atomic mass atomic mass = # protons + # neutrons.
Atomic mass includes the total mass of protons, neutrons, and electrons in an atom. Since protons and neutrons contribute significantly to the mass of an atom, atomic mass is generally greater than atomic number, which represents the number of protons in the nucleus. Electrons have a much smaller mass compared to protons and neutrons, so they have less impact on the overall atomic mass.
Mass number = number of protons + number of neutrons in an atom
Atomic number: number of protons in a nucleus unique to an element Atomic Mass number: number of protons + number of neutrons in a nucleus. May be a small range of values for a given element. Very roughly the atomic mass number is double the atomic number. For large elements it is more than double.
The number of neutrons in an atom is easily calculated by taking the mass number and subtracting the atomic number. Take for example, Uranium: the mass number on the periodic table is 238, while the atomic number is 92. Take the difference of 238 and 92 and that will be equal to the number of neutrons. 238-92=146
No. The atomic number only counts the number of protons or electrons in an atom, but the mass number counts at least the number of protons, sometimes the electrons and the number of neutrons if any. The closest they will get is being the same (Hydrogen with AN=1, MN=1), but the mass number will almost always be bigger than the atomic number.
Calcium has atomic number of 20, an atomic weight of 40.078 and an mass numbers of 40 - 48 inclusive in its isotopes. Atomic number is the count of protons in the nucleus. Mass number is the count of protons plus neutrons. The question refers to atomic mass rather than atomic weight. Atomic mass normally refers to the mass of a specific isotope of an element and is related to the mass number. Atomic weight ( or relative atomic mass as it is termed by IUPAC) the average mass of naturally occurring isotopes of an element. The relationship between mass number and atomic mass is defined in terms of the Atomic mass unit which is in simple terms 1/12 of the mass of a 12C atom. If you need to find out more about the relationship between mass number and and atomic mass you need to read the article "atomic mass unit" in wikipedia.