Chlorine how many protons

The atomic weights given inside the back cover of this book are all weighted averages of the isotopes occurring in nature, and these are the figures we shall use henceforth-unless we are specifically discussing one isotope. All isotopes of an element behave the same way chemically for the most part. Their behavior will differ in regard to mass-sensitive properties such as diffusion rates, which we'll look at later in this book.

Magnesium Mg has three significant natural isotopes: How many protons and neutrons are present in each of these three isotopes? How do we write the symbols for each isotope? Finally, what is the weighted average of the atomic weights? There are 12 protons in all magnesium isotopes.

The isotope whose atomic weight is The symbol for this isotope is 24Mg. Similarly, the isotope whose atomic weight is The third isotope We calculate the average atomic weight as follows:.

Boron has two naturally occurring isotopes, lO B and 11 B. We know that From the natural atomic weight given on the inside back cover, calculate the atomic weight of the lO B isotope.

If We can use W to represent the unknown atomic weight in our calculation:. Dickerson, H. Gray, and G. Haight, Jr. Content was used from "Chemical Principles", an introductory college-level text for General Chemistry with permission of the Caltech library and Harry B.

Gray, on behalf of the authors. Figure Four isotopes of helium He. All atoms of helium have two protons hence two electrons , but the number of neutrons can vary. The overall charge on an atom is 0, therefore there must be an equal number of protons and electrons in an atom so that the charges cancel out. So in chlorine, we can see that the atomic number is This means that each chlorine atom has 17 protons and therefore must also have 17 electrons.

The nucleus of an atom contains protons and neutrons. The nucleus is the main contributor to the mass of the atom, meaning that the mass number can tell us the number of protons and neutrons in an atom. Protons carry a positive charge. Each proton in an atom's nucleus must be balanced with a negatively charged electron in one of the 'shells' outside the nucleus.

The number of electrons in an atom's outer shell determines the atom's chemical properties. Adding or removing protons changes the number and arrangement of electrons in the outer shell which changes how that atom reacts with other atoms.

Neutrons don't change things greatly because they do not carry an electrical charge. Neutrons can be added or removed from an atom and the electrons around the atom really don't care that much. Questions and Answers Previous Question Is krypton dangerous?