Q: (a) What is an isotope?
(b) Why are the atomic weights of the elements not integers? Cite two reasons.
Solution:
(a) When two or more atoms of an element have different atomic masses, each is termed an isotope.
(b) The atomic weights of the elements ordinarily are not integers because:
(1) the atomic masses of the atoms generally are not integers (except for 12 C)
(2) the atomic weight is taken as the weighted average of the atomic masses of an atom s naturally occurring isotopes.
Q: Cite the difference between atomic mass and atomic weight.
Solution:
Atomic mass is the mass of an individual atom, whereas atomic weight is the average (weighted) of the atomic masses of an atom s naturally occurring isotopes.
Q: (a) What electron subshell is being filled for the rare earth series of elements on the periodic table?
(b) What electron subshell is being filled for the actinide series?
Solution:
(a) The 4f subshell is being filled for the rare earth series of elements.
(b) The 5f subshell is being filled for the actinide series of elements.
Q: (a) Briefly cite the main differences between ionic, covalent, and metallic bonding.
(b) State the Pauli exclusion principle.
Solution:
(a) The main differences between the various forms of primary bonding are:
Ionic--there is electrostatic attraction between oppositely charged ions.
Covalent--there is electron sharing between two adjacent atoms such that each atom assumes a stable electron configuration.
Metallic--the positively charged ion cores are shielded from one another, and also "glued" together by the sea of valence electrons.
(b) The Pauli exclusion principle states that each electron state can hold no more than two electrons, which must have opposite spins.
المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .
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