Chlorine is a yellow-green gas at room temperature. It is an extremely reactive element and a strong oxidising agent: among the elements, it has the highest electron affinity and the third-highest electronegativity, behind only oxygen and fluorine.
While perhaps best known for its role in providing clean drinking water, chlorine chemistry also helps provide energy-efficient building materials, electronics, fiber optics, solar energy cells, 93 percent of life-saving pharmaceuticals, 86 percent of crop protection compounds, medical plastics, and much more.
Elemental chlorine is commercially produced from brine by electrolysis, predominantly in the chlor-alkali process.
Protons and Neutrons in Chlorine
Chlorineis a chemical element with atomic number17 which means there are 17 protons in its nucleus. Total number of protons in the nucleus is called theatomic numberof the atom and is given thesymbol Z. The total electrical charge of the nucleus is therefore +Ze, where e (elementary charge) equals to1,602 x 10-19coulombs.
The total number ofneutronsin the nucleus of an atom is called theneutronnumberof the atom and is given thesymbol N. Neutronnumber plusatomic numberequals atomic mass number:N+Z=A. The difference between the neutron number and the atomic number is known as theneutron excess: D = N – Z = A – 2Z.
For stable elements, there is usually a variety of stable isotopes. Isotopes are nuclides that have the same atomic number and are therefore the same element, but differ in the number of neutrons. Mass numbers of typical isotopes of Chlorineare35; 37.
Main Isotopes of Chlorine
Chlorine has two stable isotopes, 35Cl and 37Cl. These are its only two natural isotopes occurring in quantity, with 35Cl making up 76% of natural chlorine and 37Cl making up the remaining 24%.The longest-lived radioactive isotope is 36Cl, which has a half-life of 301,000 years. All other isotopes have half-lives under 1 hour, many less than one second.
Chlorine-35 is composed of 17 protons, 18 neutrons, and 17 electrons.
Chlorine-37 is composed of 17 protons, 20 neutrons, and 17 electrons.
Chlorine-36 is composed of 17 protons, 19 neutrons, and 17 electrons. Trace amounts ofradioactive36Cl exist in the environment, in a ratio of about 7×10−13to 1 with stable isotopes.36Cl is produced in the atmosphere byspallationof36Arby interactions withcosmic rayprotons.
Typical Unstable Isotopes
Electrons and Electron Configuration
The number of electrons in an electrically-neutral atom is the same as the number of protons in the nucleus. Therefore, the number of electrons in neutral atom of Chlorine is 17. Each electron is influenced by the electric fields produced by the positive nuclear charge and the other (Z – 1) negative electrons in the atom.
Since the number of electrons and their arrangement are responsible for the chemical behavior of atoms, theatomic numberidentifies the various chemical elements. The configuration of these electrons follows from the principles of quantum mechanics. The number of electrons in each element’s electron shells, particularly the outermost valence shell, is the primary factor in determining its chemical bonding behavior. In the periodic table, the elements are listed in order of increasing atomic number Z.
Electron configuration ofChlorineis[Ne] 3s23p5.
Possible oxidation states are+1,5,7/-1.
It is an extremely reactive element and a strong oxidising agent: among the elements, it has the highest electron affinity and the third-highest electronegativity on the Pauling scale, behind only oxygen and fluorine. Because of its great reactivity, all chlorine in the Earth’s crust is in the form of ionic chloride compounds, which includes table salt. It is the second-most abundant halogen (after fluorine) and twenty-first most abundant chemical element in Earth’s crust.
Common Compound of Chlorine
The simplest chlorine compound is hydrogen chloride, HCl, a major chemical in industry as well as in the laboratory, both as a gas and dissolved in water as hydrochloric acid. It is often produced by burning hydrogen gas in chlorine gas, or as a byproduct of chlorinating hydrocarbons. Hydrogen chloride gas and hydrochloric acid are important in technology and industry.
A protonis one of thesubatomic particlesthat make up matter. In the universe, protons are abundant, making upabout halfof all visible matter. It hasa positive electric charge (+1e)and a rest mass equal to 1.67262 × 10−27kg (938.272 MeV/c2)— marginally lighter than that of the neutron but nearly 1836 times greater than that of the electron. The proton has a mean square radius of about 0.87 × 10−15m, or 0.87 fm, and it is a spin – ½ fermion.
The protonsexist in the nuclei of typical atoms, along with their neutral counterparts, the neutrons. Neutrons and protons, commonly callednucleons, are bound together in the atomic nucleus, where they account for 99.9 percent of the atom’s mass. Research in high-energy particle physics in the 20th century revealed that neither the neutron nor the protonis notthe smallest building block of matter.
A neutronis one of thesubatomic particlesthat make up matter. In the universe, neutrons are abundant, making upmore than halfof all visible matter. It hasno electric chargeand a rest mass equal to 1.67493 × 10−27 kg—marginally greater than that of the proton but nearly 1839 times greater than that of the electron. The neutron has a mean square radius of about 0.8×10−15 m, or 0.8 fm, and it is a spin-½ fermion.
Atomic nuclei consist of protons and neutrons, which attract each other throughthe nuclear force, while protons repel each other viathe electric forcedue to their positive charge. These two forces compete, leading to various stability of nuclei. There are only certain combinations of neutrons and protons, which formsstable nuclei.
Neutrons stabilize the nucleus, because they attract each other and protons , which helps offset the electrical repulsion between protons. As a result, as the number of protons increases,an increasing ratio of neutrons to protons is neededto form a stable nucleus. If there are too many or too few neutrons for a given number of protons, the resulting nucleus is not stable and it undergoesradioactive decay.Unstable isotopesdecay through various radioactive decay pathways, most commonly alpha decay, beta decay, or electron capture. Many other rare types of decay, such as spontaneous fission or neutron emission are known. It should be noted that all of these decay pathways may be accompanied bythe subsequent emission ofgamma radiation. Pure alpha or beta decays are very rare.
About Electrons and Electron Configuration
The periodic table is a tabular display of the chemical elements organized on the basis of their atomic numbers, electron configurations, and chemical properties. The electron configuration is the distribution of electrons of an atom or molecule (or other physical structure) in atomic or molecular orbitals. Knowledge of theelectron configurationof different atoms is useful in understanding the structure of the periodic table of elements.
Every solid, liquid, gas, and plasma is composed of neutral or ionized atoms. Thechemical properties of the atomare determined by the number of protons, in fact, by number andarrangement of electrons. Theconfiguration of these electronsfollows from the principles of quantum mechanics. The number of electrons in each element’s electron shells, particularly the outermost valence shell, is the primary factor in determining its chemical bonding behavior. In the periodic table, the elements are listed in order of increasing atomic number Z.
It is thePauli exclusion principlethat requires the electrons in an atom to occupy different energy levels instead of them all condensing in the ground state. The ordering of the electrons in the ground state of multielectron atoms, starts with the lowest energy state (ground state) and moves progressively from there up the energy scale until each of the atom’s electrons has been assigned a unique set of quantum numbers. This fact has key implications for the building up of the periodic table of elements.
The first two columns on the left side of the periodic table are where thessubshells are being occupied. Because of this, the first two rows of the periodic table are labeled thes block. Similarly, thep blockare the right-most six columns of the periodic table, thed blockis the middle 10 columns of the periodic table, while thef blockis the 14-column section that is normally depicted as detached from the main body of the periodic table. It could be part of the main body, but then the periodic table would be rather long and cumbersome.
For atoms with many electrons, this notation can become lengthy and so an abbreviated notation is used. The electron configuration can be visualized as the core electrons, equivalent to thenoble gasof the preceding period, and the valence electrons (e.g. [Xe] 6s2 for barium).
Oxidation states are typically represented by integers which may be positive, zero, or negative. Most elements have more than one possible oxidation state. For example, carbon has nine possible integer oxidation states from −4 to +4.
The current IUPAC Gold Book definition of oxidation state is:
“Oxidation state of an atom is the charge of this atom after ionic approximation of its heteronuclear bonds…”
and the term oxidation number is nearly synonymous. An element that is not combined with any other different elements has an oxidation state of 0. Oxidation state 0 occurs for all elements – it is simply the element in its elemental form. An atom of an element in a compound will have a positive oxidation state if it has had electrons removed. Similarly, adding electrons results in a negative oxidation state. We have also distinguish between the possible and common oxidation states of every element. For example, silicon has nine possible integer oxidation states from −4 to +4, but only -4, 0 and +4 are common oxidation states.
|Number of protons||17|
|Number of neutrons (typical isotopes)||35; 37|
|Number of electrons||17|
|Electron configuration||[Ne] 3s23p5|
Properties of other elements
Periodic Table in 8K resolution
Other properties of Chlorine
Chlorine has an atomic number of 17 and an atomic mass of 35.45, meaning that an atom of chlorine consists of 17 protons, 17 electrons, and 18 neutrons.What is the complete electron configuration for chlorine? ›
Therefore the Chlorine electron configuration will be 1s22s22p63s23p5. The configuration notation provides an easy way for scientists to write and communicate how electrons are arranged around the nucleus of an atom. This makes it easier to understand and predict how atoms will interact to form chemical bonds.Which is the correct electron configuration of chlorine Z 17 A 35? ›
The neutral atom chlorine (Z=17), for instance has 17 electrons. Therefore, its ground state electronic configuration can be written as 1s22s22p63s23p5. The chloride ion (Cl-), on the other hand, has an additional electron for a total of 18 electrons.What is element 1s2 2s2 2p6 3s2 3p6 4s1? ›
An element having configuration 1 s 2 2 s 2 2 p 6 3 s 2 3 p 6 4 s 1 is Potassium.Does chlorine have 17 or 18 electrons? ›
For example, every chlorine atom has 17 electrons and 17 protons; its atomic number is 17. However, three out of four chlorine atoms weigh 35 amu (17 protons and 18 neutrons) and the fourth weighs 37 amu (17 protons and 20 neutrons).What is a chlorine atom that has ____ protons and neutrons called? ›
While a chlorine atom always has 17 protons, it can have any number of neutrons. Two atoms with the same number of protons and different number of neutrons are called isotopes. Two naturally occurring stable isotopes exist for chloride. One has 18 neutrons and the other has 20 neutrons.How do you find the number of protons and neutrons in chlorine? ›
In chlorine atom (Cl), Number of protons (Z) = 17. Number of neutrons = A — Z = 35 — 17 = 18.How many protons and neutrons are in each nucleus for chlorine-35 and chlorine 37? ›
An atom of chlorine-35 contains 18 neutrons (17 protons + 18 neutrons = 35 particles in the nucleus) while an atom of chlorine-37 contains 20 neutrons (17 protons + 20 neutrons = 37 particles in the nucleus). Adding or removing a neutron from an atom's nucleus creates isotopes of a particular element.What is the neutron number of chlorine-35 and chlorine 37? ›
|Chlorine atom, 35Cl||17||18|
|Chlorine atom, 37Cl||17||20|
|Naturally occurring mixture of chlorine||17||18 or 20|
|Uranium atom, 234U||92||142|
An atom of chlorine-35 contains 18 neutrons (17 protons + 18 neutrons = 35 particles in the nucleus) while an atom of chlorine-37 contains 20 neutrons (17 protons + 20 neutrons = 37 particles in the nucleus). Adding or removing a neutron from an atom's nucleus creates isotopes of a particular element.
). Its nucleus contains 17 protons and 20 neutrons for a total of 37 nucleons. Chlorine-37 accounts for 24.23% of natural chlorine, chlorine-35 accounting for 75.77%, giving chlorine atoms in bulk an apparent atomic weight of 35.453(2) g/mol.Why does chlorine have 20 neutrons? ›
An element with 17 protons will always be chlorine. However an element's mass numbers can vary, which means that it can have different numbers of neutrons. So although chlorine has a mass number of 35 which means it has 18 neutrons, it can also have a mass number of 37, which means it has 20 neutrons.What has 17 protons and 20 neutrons? ›
Chlorine-37, the nucleus of which consists of 17 protons and 20 neutrons, is a different nuclide from sodium-23 (nucleus of 11 protons and 12 neutrons) or chlorine-35 (nucleus of 17 protons and 18 neutrons).