Elements
So what exactly is an element? Perhaps the simplest answer is that an element is a substance which contains only one type of atom. The simplest element in the periodic table is of course Hydrogen, its simplest form containing a single proton in the nucleus and a single electron orbiting in its first shell. All elements have a symbolic representation as shown in the periodic table, in the case of hydrogen it is quite simply this:
Starting from the top left corner, the number one represents the atomic or proton number, followed by the chemical symbol itself which in this particular case is a single H. We then have the full name of the element beneath that followed by the relative atomic mass, in the case of hydrogen this being 1.008.the relative atomic mass, or mass number represents the total number of protons and neutrons in the nucleus. In the case of this particular isotope of hydrogen there are no neutrons, but the number 1.008 follows from the fact that hydrogen exists in one or more isotopes, and these are taken into consideration when the relative atomic mass (if you like the sort of average) is calculated. If you wish to read more about isotopes now then click on the link which follows: < Isotopes >
Q. What is an element?
A. An element is a substance which contains only one type of atom.
Q. What does the atomic number tell you about the atom?
A. The atomic number tells you how many protons you will find in the nucleus of an atom of that particular element.
Q. What is the mass number?
A. The mass number is the total number of protons and neutrons in the nucleus of the atom.
Q. How would you calculate the number of neutrons in the nucleus given the relative atomic mass and the atomic number?
A. The relative atomic mass gives you the number of protons and neutrons, the atomic number gives you the number of protons only. If you take the atomic number away from the relative atomic mass you will be left with the number of neutrons, for example in the element carbon, one of its isotopes holds a relative atomic mass of twelve and its proton or atomic number, is six. Therefore the number of neutrons in this particular isotope of carbon is 12-6 which equal six.