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The atomic number is the number of protons in the nucleus of an atom, denoted by 'Z'. It uniquely identifies an element, as all atoms of a given element have the same atomic number.
The mass number is the total number of protons and neutrons in an atom's nucleus. It is calculated by adding the number of protons to the number of neutrons.
Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons. This results in different mass numbers for the isotopes.
Isobars are atoms of different elements that have the same mass number but different atomic numbers. This means they have different numbers of protons and neutrons.
Isotopes are used in medical applications, such as in cancer treatment with radioactive isotopes, and in archaeological dating, such as carbon dating to determine the age of ancient artifacts.
Na+ has lost one electron, resulting in a stable electron configuration with a filled K shell (2 electrons) and a filled L shell (8 electrons). This configuration is similar to that of the noble gas neon, making it stable.
To calculate the average atomic mass, multiply the mass of each isotope by its relative abundance, then sum the results: (79 * 0.497) + (81 * 0.503) = 80.0 u.
Let x be the percentage of 16X and (100-x) be the percentage of 18X. The equation 16x + 18(100-x) = 16.2 leads to x = 90% for 16X and 10% for 18X.
The element with atomic number Z = 3 is lithium (Li), and its valency is 1, as it has one electron in its outermost shell that it can lose to achieve a stable configuration.
The mass number of species X is 134 (66 protons + 68 neutrons) and for species Y, it is also 134. Since they have the same mass number but different atomic numbers, they are isobars.
False. J.J. Thomson proposed the 'plum pudding' model, which suggested that electrons are embedded in a positive sphere, not that the nucleus contains only nucleons.
False. A neutron is a subatomic particle that is not formed by an electron and a proton; it is a distinct particle found in the nucleus of an atom.
The valency can be determined by the number of electrons in the outermost shell. Chlorine has a valency of 1, sulfur has a valency of 2, and magnesium has a valency of 2.
The maximum number of electrons that can be accommodated in the outermost shell is 8, following the octet rule, which states that atoms are most stable with eight electrons in their outer shell.
The Bohr-Bury scheme describes how electrons are arranged in shells around the nucleus, indicating that electrons fill inner shells before outer shells and that each shell has a maximum capacity.
Rutherford's experiment revealed that most of the atom is empty space, with a small, dense nucleus containing protons at the center, around which electrons orbit.
Neutrons contribute to the mass of an atom along with protons. While protons determine the atomic number, neutrons affect the mass number and stability of the nucleus.
The average atomic mass of an element is calculated based on the weighted average of the masses of its isotopes, taking into account their relative abundances in nature.
The electron configuration of carbon (atomic number 6) is 1s² 2s² 2p², indicating that it has two electrons in the first shell and four in the second shell.
The electron configuration of sodium (atomic number 11) is 1s² 2s² 2p⁶ 3s¹, showing that it has two electrons in the first shell, eight in the second, and one in the third shell.
Valence electrons are the electrons in the outermost shell of an atom and determine how an element reacts chemically. Elements tend to gain, lose, or share valence electrons to achieve a stable electron configuration.