Atomic Number Of Cl



The group 17 consists of halogens. The halogen present in third period is chlorine (Cl) with atomic number (Z) = 17. What is the basic difference in the electronic configuration of the elements belonging to group 1 and group 2? Recall that the symbol for an element or ion is as follows: From the periodic table, we can see that the atomic number of Cl is 17. The atomic number tells us the number of protons, which means Cl has 17 protons. Click to see full answer. Simply so, what is the number of protons in chlorine? Atomic number is the number of protons in the nucleus. Atomic number of Cl is 17. In case of Cl-: There is one more electron in the shell due to which charge on chlorine is negative and it now called as ion.

Learning Objective

  • Determine the relationship between the mass number of an atom, its atomic number, its atomic mass, and its number of subatomic particles

Key Points

  • Neutral atoms of each element contain an equal number of protons and electrons.
  • The number of protons determines an element’s atomic number and is used to distinguish one element from another.
  • The number of neutrons is variable, resulting in isotopes, which are different forms of the same atom that vary only in the number of neutrons they possess.
  • Together, the number of protons and the number of neutrons determine an element’s mass number.
  • Since an element’s isotopes have slightly different mass numbers, the atomic mass is calculated by obtaining the mean of the mass numbers for its isotopes.

Atomic Number of Chlorine is 17. Chemical symbol for Chlorine is Cl. Number of protons in Chlorine is 17. Atomic weight of Chlorine is 35.45 u or g/mol. Melting point of Chlorine is -34,6 °C and its the boiling point is -101 °C. How to Write the Electron Configuration for Chlorine (Cl) In order to write the Chlorine electron configuration we first need to know the number of electrons for the Cl atom (there are 17 electrons). When we write the configuration we'll put all 17 electrons in orbitals around the nucleus of the Chlorine.

Terms

  • atomic massThe average mass of an atom, taking into account all its naturally occurring isotopes.
  • mass numberThe sum of the number of protons and the number of neutrons in an atom.
  • atomic numberThe number of protons in an atom.

Atomic Number

Neutral atoms of an element contain an equal number of protons and electrons. The number of protons determines an element’s atomic number (Z) and distinguishes one element from another. For example, carbon’s atomic number (Z) is 6 because it has 6 protons. The number of neutrons can vary to produce isotopes, which are atoms of the same element that have different numbers of neutrons. The number of electrons can also be different in atoms of the same element, thus producing ions (charged atoms). For instance, iron, Fe, can exist in its neutral state, or in the +2 and +3 ionic states.

Mass Number

An element’s mass number (A) is the sum of the number of protons and the number of neutrons. The small contribution of mass from electrons is disregarded in calculating the mass number. This approximation of mass can be used to easily calculate how many neutrons an element has by simply subtracting the number of protons from the mass number. Protons and neutrons both weigh about one atomic mass unit or amu. Isotopes of the same element will have the same atomic number but different mass numbers.

Scientists determine the atomic mass by calculating the mean of the mass numbers for its naturally-occurring isotopes. Often, the resulting number contains a decimal. For example, the atomic mass of chlorine (Cl) is 35.45 amu because chlorine is composed of several isotopes, some (the majority) with an atomic mass of 35 amu (17 protons and 18 neutrons) and some with an atomic mass of 37 amu (17 protons and 20 neutrons).

Given an atomic number (Z) and mass number (A), you can find the number of protons, neutrons, and electrons in a neutral atom. For example, a lithium atom (Z=3, A=7 amu) contains three protons (found from Z), three electrons (as the number of protons is equal to the number of electrons in an atom), and four neutrons (7 – 3 = 4).

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Atomic Number Of Cl

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Atomic Number Of Cl

Atomic number of chlorine-37

Atomic Number Chart

http://cnx.org/content/m44390/latest/?collection=col11448/latest
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