![]() ![]() Give the identity of a particle with 53 protons, 74 neutrons and 54 electrons: Protons = 53 which is the atomic number of iodine Protons + neutrons = 53 + 74 = 127 so isotope is iodine-127 One more electron than protons so an ion with a 1- charge: 127I - Isotopesĭefinition: Isotopes of an element have the same number of protons (same atomic number) but different numbers of neutrons.īecause they have the same electronic structure, isotopes of an element have the same chemical properties, but they have different physical properties – most notably different masses. Neutrons = 45-21=24 (it is the same isotope) Electrons = 21-3 = 18 (a 3+ ion means 3 electrons have been lost) What is the number of protons, neutrons and electrons in an Sc 3+ ion of the same isotope? Protons = 21 (it is still scandium) What is the number of protons, neutrons and electrons in an atom of scandium-45? Protons = 21 (look it up on periodic table) Neutrons = 45-21 = 24 (given mass number - number of protons) Electrons = 21 (equal to number of protons for an atom) An ion with a negative charge has gained electrons – again the magnitude of the charge indicates how many electrons have been gained. The magnitude of the charge indicates the number of electrons that have been lost. An ion with a positive charge has lost electrons (there are now more protons than electrons). While atoms do not lose or gain protons or neutrons, they can lose or gain electrons to become ions with an overall charge. Therefore number of neutrons = mass number – atomic numberīecause an atom has no overall charge, there must be exactly the same number of electrons as protons in an atom. The total number of protons and neutrons (nucleons) in an atom is the mass number. The periodic table is arranged in order of increasing atomic number – each different type of atom is identified by its unique number of protons. ![]() The number of protons in an atom is the atomic number. Numbers of protons, neutrons and electrons Most of an atom is empty space – protons, neutrons and electrons are very small compared to atoms, but because protons and neutrons weigh much more than electrons, virtually all the mass in an atom is in the nucleus. The nucleus (containing the protons & neutrons) has an overall positive charge, and the electrons orbiting around it are negatively charged, so an atom has charge distribution – positive in the middle and negative surrounding this region. Overall, the periodic table with charges is useful to help determine the nature of the chemical element in its ionic form, i.e., whether it loses or gains electrons to achieve the nearest inert gas configuration.The particles from which atoms are made are protons, neutrons and electrons. For example, helium (with atomic number 2) has a complete first shell, while in case of neon with atomic number 10, 2 electrons fill the first shell and the remaining 8 occupy the second shell, thus making the element inert. In case of inert gases or noble gases (the helium group), the electrons fill up the shell completely and their charge is zero. So, to achieve a complete shell (nearest inert gas, neon like configuration), it donates its 1 electron, thus having a charge +1 (represented as Na 1+). ![]() Over here, the electronic configuration is 2 electrons in the S shell, 8 in the P shell, and remaining 1 in the outer D shell. Let’s take an example of sodium (Na) that has atomic number 11. Thus, according to this method, 2 electrons are allotted in the first shell, 8 electrons in the second shell, and 18 electrons in the third shell. In order to find out the charge, first examine the configuration of electrons in the orbitals or shells (S, P, D, and F shells) as per the 2n 2 rule (where ‘n’ is the number of shells). Briefly speaking, the charge of an element in its ionic form refers to the actual number of electrons that it loses or gains to achieve the nearest noble gas configuration. And a periodic table with atomic mass and charges interprets both the charges and atomic mass. Likewise, the periodic table with charges illustrates elements with the probable charges, when they are in the ionic form. You may also come across periodic table with atomic mass that gives a simplified view of the elements with their respective mass numbers (total number of protons and neutrons). This labeled periodic table of element with names and their atomic number helps in easy interpretation of the properties of elements. Thus, instead of sorting elements as per their mass number (which is so in Mendeleev periodic table), elements are arranged from left to right, according to increasing order of the atomic number. The modern periodic table of elements, or just periodic table, is a tabular representation of the identified elements (as of date 118) along with their respective symbolic name and atomic number. ![]()
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