1. Explain why the atoms of elements in Groups IA, IIA, and IIIA of the Periodic
ID: 903786 • Letter: 1
Question
1. Explain why the atoms of elements in Groups IA, IIA, and IIIA of the Periodic Table tend to lose electrons, while atoms of elements in Groups VA,VIA, and VIIA tend to gain electrons. How many electrons are gained or lost by the atoms of these elements? What charge do they carry when they exist as ions?
2. Explain why atoms in Groups I have low electronegativity values, while those in groups VII have high electronegativities.
3. What kind of bond exists between two O atoms in O2? How many electrons are shared between the two O atoms? How does a double bond differ from a single bond or a triple bond? Answer the same questions for N2.
4. Indicate what is meant by the term “like dissolves like”.
5. a) Predict whether N2 will be more soluble in water (polar covalent substance) or gasoline (covalent substance)?
b) If ascorbic acid is soluble in water, would you expect it to be soluble in fat ( another covalent substance)?
c) If vitamin A is soluble in fat, would you expect it to be soluble in water?
d) Would you expect HF to be soluble in water? In oil?
e) Would you expect NaCl to be soluble in gasoline?
thanks!
Explanation / Answer
First, the elements of group 1, 2 and 3, they are all metals and all of these metals have The elements have one, two and three electrons in their outer electronic shell.
Most metallic elements have a shiny luster, have high melting points, are good conductors of heat and electricity, are malleable (can be pounded into thin sheets), are ductile (can be drawn into wires). Metals tend to have low ionization energies and lose electrons relatively easily to form positive ions.
Second, when they are in solution, in order to get a noble gas configuration, they need to lose some electrons to do this. In the first group they lose 1, second two and the third three electrons.
On the other hand, elements of the group 15,16, and 17 (VA, VIA and VIIA) they are all nonmetals and Nonmetals vary greatly in appearance. Most are not lustrous, have low melting points, are poor conductors of heat and electricity, and not malleable or ductile.
Because of their electron affinities, nonmetals tend to gain electrons relatively easily to form negative ions. Compounds composed entirely of nonmetals are molecular substances.
In order to get the noble gas configuration, they tend to gain 3, 2 and 1 electron. (15, 16 and 17).
When they exist as ions, they hold the same charge of the electrons gained or lose. For example Na can lose 1 electron, so the charge it holds in ions it's 1+, on the other hand, when the S gain electrons (2 electrons) it holds the charge 2-.
2. Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons. Is a chemical property that describes the tendency of an atom or a functional group to attract electrons (or electron density) towards itself. An atom's electronegativity is affected by both its atomic number and the distance at which its valence electrons reside from the charged nucleus. The higher the associated electronegativity number, the more an element or compound attracts electrons towards it. The Pauling scale is the most commonly used. Fluorine (the most electronegative element) is assigned a value of 4.0, and values range down to cesium and francium which are the least electronegative at 0.7.
The distance of the electrons from the nucleus remains relatively constant in a periodic table row, but not in a periodic table column. The force between two charges is given by Coulomb’s law:
F = k q1q2/r2
In this expression, q represents a charge, k represents a constant and r is the distance between the charges. When r = 2, then r2= 4. When r = 3, then r2 = 9. When r = 4, then r2 = 16. It is readily seen from these numbers that, as the distance between the charges increases, the force decreases very rapidly. This is called an exponential change.
The result of this change is that electronegativity increases from bottom to top in a column in the periodic table even though there are more protons in the elements at the bottom of the column. Elements at the top of a column have greater electronegativities than elements at the bottom of a given column.
The overall trend for electronegativity in the periodic table is diagonal from the lower left corner to the upper right corner. Since the electronegativity of some of the important elements cannot be determined by these trends (they lie in the wrong diagonal), we have to memorize the following order of electronegativity for some of these common elements.
4. this term means that polar substances dissolve other polar substances and will not dissolve nonpolar substances; on the other hand nonpolar substances dissolve other nonpolar substances and will not dissolve polar substances.
The other two questions, I would love to answer those, but please post them in a new question to answer better and faster.
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