An atom's mass indicates how many protons and neutrons it contains in its nucleus, since electrons have such small mass relative to them. This is also known as Atomic Mass.
Protons and neutrons. Electrons have a too little mass.
The mass number of an atom is the average of all it's isotopes in ratio to how often an isotope occurs naturally (abundance). An isotope is a variant of an element that has a different number of neutrons, therefore causing the atom to have a different mass. The percent abundance of an isotope is converted to a fraction, and multiplied by the mass of the isotope. Then all the factional masses of different isotopes are added together. Atomic mass = (mass isotope 1)x(fractional natural abundance of isotope 1) + (mass isotope 2)x(fractional natural abundance of isotope 2) + (mass isotope 3)x(fractional natural abundance of isotope 3) For example: Hydrogen has 3 naturally occurring isotopes: Protium - Abundance - 99.985% (.99985) Mass - 1.0078 Deuterium - Abundance - .015% (.00015) Mass - 2.014 Tritium - Abundance - 0% (.000) Mass - 3.016 Atomic mass number of Hyrdogen = (.99985)(1.0078) + (.00015)(2.014) + (.000)(3.016) = 1.00795 Go look up the mass number of Hydrogen on the periodic table and it says 1.008
atomic mass and mass number are differernt because atomic mass mean mass of whole atom which mean mass of proton,neutron and electron while mass number is number of proton and neutron only.zahid ullah paf college risalpur
the number of protons determine what the substance is. if the number of protons in an atom change, the substance made of that atom changes too.
Atomic mass is the average of the masses of the naturally existing (i.e. mixture of) isotopes of one specific element.Mass number is the sum of protons and neutrons in the atomic nucleus of an isotope.Atomic mass: the mass of an isotope in the neutral state expressed in 1/12 from the mass of 12C.IUPAC recommend the use of the expression atomic mass for isotopes and atomic weight for chemical elements.
If I remember right, from my chemistry class, I think the mass number is the mass of the atom. Electrons have negligent mass- they aren't big enough to make a significant difference in the counting, so they aren't counted. Protons have a mass of 1 each. They are attracted to electrons. Neutrons also have a mass of about 1. They have no particular attraction, but they will connect to protons in the atom's nucleus (as long as there aren't too many, depending on the amount of protons), and increase the mass by 1 each. So, the mass number should be the number of neutrons+ the number of protons. (The electrons are about a 2000th of that mass)
Platinum is a rare element too. Atomic number of platinum is 78.
It is the nucleus. Mass of electrons is too small
Protons and neutrons. Electrons have a too little mass.
The mass number of an atom is the average of all it's isotopes in ratio to how often an isotope occurs naturally (abundance). An isotope is a variant of an element that has a different number of neutrons, therefore causing the atom to have a different mass. The percent abundance of an isotope is converted to a fraction, and multiplied by the mass of the isotope. Then all the factional masses of different isotopes are added together. Atomic mass = (mass isotope 1)x(fractional natural abundance of isotope 1) + (mass isotope 2)x(fractional natural abundance of isotope 2) + (mass isotope 3)x(fractional natural abundance of isotope 3) For example: Hydrogen has 3 naturally occurring isotopes: Protium - Abundance - 99.985% (.99985) Mass - 1.0078 Deuterium - Abundance - .015% (.00015) Mass - 2.014 Tritium - Abundance - 0% (.000) Mass - 3.016 Atomic mass number of Hyrdogen = (.99985)(1.0078) + (.00015)(2.014) + (.000)(3.016) = 1.00795 Go look up the mass number of Hydrogen on the periodic table and it says 1.008
The number of protons in an atomic nucleus is the sole determinate as regards its elemental identity - its atomic number. The number of electrons will exactly match this number in the neutral atom. But electrons can be loaned or borrowed. What is known? The number of neutrons? With nothing more than is stated, what can be determined? Nothing of a certainty. If the number of neutrons is known, then we could divide the table of elements into two parts: the group of elements that it "could be" and the group that it "couldn't be" by using a table of nuclides as a reference. Other than that, there is little that can be discovered....
Scientists can disregard the mass of electrons when determining the mass of an atom because the mass of electrons is significantly smaller than the mass of protons and neutrons. Therefore, the mass of electrons has a negligible impact on the overall mass of an atom.
Atomic number of an element is the number of protons that an atom of an element contains. The atomic weight (the mass of the atom) is measured by not only the mass of the proton(s), but by the mass of the nuetrons and electrons too.
An atom contains an equal amount of positively charged particles (protons) and negatively charged particles (electrons). If a atom gains or loses electrons it then gains a charge and is no longer known as an atom; it becomes an ion.
atomic mass and mass number are differernt because atomic mass mean mass of whole atom which mean mass of proton,neutron and electron while mass number is number of proton and neutron only.zahid ullah paf college risalpur
depends on the proton number of the atom, for nitrogen it's 7 so there are 7. The mass number is the number of protons and neutrons so if you subtract the proton number you get the number of neutrons too
The atomic number is the number of protons in the nucleus of an atom. The number of protons in an atom's nucleus determines the chemical identity of that atom. It tells us which element it is. The elemental identity of an atom is determined by the number of protons in that atom's nucleus. This was bit repetitive, but it is a critical concept in chemistry and physics. Atomic Mass might be thought of as the "weight" of an atom. Atomic mass is found by adding up the masses of all the protons, neutrons, and electrons in the atom. As electrons weigh less than 1/1800th of what a proton weighs, they contribute only the smallest amount to the weight of the atom (compared to the protons and neutrons), regardless of which atom it is. These weights are expressed in atomic mass units because the "normal" terms for the expression of weight (mass) are far too large to be "easy to work with" on the atomic scale. Let's do a quick example with the two stable isotopes of lithium. Lithium is element number three on the Periodic Table. It has 3 protons in its nucleus, and 3 is its atomic number. (Repeating, the number of protons in the nucleus is equal to the atomic number, and this identifies the element under investigation.) Lithium has one "version" or isotope that has 3 neutrons. The atomic mass of 3Li is about 6.015 or so. Note: subtracting the atomic number from the atomic mass gives us the number of neutrons in the nucleus of that atom. The 6.015 minus the 3 yields an answer of 3 for the number of neutrons. There is also a lithium atom that has 4 neutrons in its nucleus. It's 4Li and its atomic mass is about 7.016 or so. Same math. Take the 7.016 and subtract the 3 and get 4 as the answer - and the number of neutrons in the nucleus of that atom. Those are the two stable isotopes of lithium. (There are a number of other isotopes of lithium, but they're all unstable and disappear fairly quickly after being made in the physics lab.)