BIOL 2112 Chapter Notes - Chapter 2: Magnesium, Electronegativity, Radionuclide
10 May 2018
School
Department
Course
Professor
Lecture 1 Study Guide
Chemical Bonds
1) The atomic mass of Magnesium is 24 Daltons and the atomic number is 12. How
many electrons does an electrically neutral Magnesium atom have? 12 How will the
atomic mass of a Magnesium atom be affected if the nucleus undergoes decay and loses
a neutron? What is the term for this form of Magnesium? Radioactive isotope, atomic
mass will decrease giving off particles and energy. If the nucleus of this Magnesium
atom continues to decay and loses a proton, what will become of the Magnesium atom?
Sodium 2) The element Aluminum (Al) has an atomic mass of 27 Daltons and an atomic
number of 13. How are the electrons of an Aluminum atom arranged in their orbitals?
Aluminum has a full 1st shell; 2 electrons; and a full 2nd shell; 8 electrons, and has only 3
valence electrons in its third shell with 5 available spots for bonding. Which of
Aluiu’s electros have the highest aout of potetial eergy? Which electros
have the lowest potential energy? Electrons differ by the amount of energy they
possess. The closest to the nucleus have the lowest energy levels while electrons in
outer orbitals possess the greatest amount of potential energy. How many valence
electrons does Aluminum have? 3 3) What feature defines a chemically reactive atom?
For an atom to be chemically reactive, it must have an incomplete valence shell – atoms
interact in order to fill their valence shells. 4) Define the term Bond Energy. When
valence electrons form bonds, their potential energy is released – bond energy. 5) List
the formal definitions of the following: A) Covalent bond Two atoms share valence
electrons B) Molecule Two or more atoms held together by covalent bonds C) Bonding
capacity Number of covalent bonds an atom can from 6) A. What is electronegativity?
An electronegative atom pulls shared electrons towards itself. B. What is the effect of
electronegativity on a covalent bond? Polarity C. How does electronegativity effect ionic
bond formation? The attraction between oppositely charged atoms or ions is an ionic
bond. An electron is transferred from the outer valence shell of one atom to the outer
valence of another atom. 7) Sodium chloride (NaCl) is an ionic compound – not a
molecule. Why? It is bonded ionically.10) A. What is a compound? A combination of two
or more elements combined in a fixed proportion by mass B. Most molecules are
compounds but compounds are not always molecules. Why? Compounds can be formed
by ionic bonds too. Molecules are formed only by covalent bonds.
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Chemical bonds: the atomic mass of magnesium is 24 daltons and the atomic number is 12. Radioactive isotope, atomic mass will decrease giving off particles and energy. Sodium 2) the element aluminum (al) has an atomic mass of 27 daltons and an atomic number of 13. Aluminum has a full 1st shell; 2 electrons; and a full 2nd shell; 8 electrons, and has only 3 valence electrons in its third shell with 5 available spots for bonding. Electrons differ by the amount of energy they possess. The closest to the nucleus have the lowest energy levels while electrons in outer orbitals possess the greatest amount of potential energy. For an atom to be chemically reactive, it must have an incomplete valence shell atoms interact in order to fill their valence shells. When valence electrons form bonds, their potential energy is released bond energy. An electronegative atom pulls shared electrons towards itself.
