Atom and Valence Electrons

Topics: Atom, Chemical bond, Chemical bonding Pages: 32 (6071 words) Published: May 14, 2013
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1.Top of Form
Arrange the following elements in order of increasing electronegativity:

germanium, bromine, selenium, arsenic
Please answer this question according to the general rules you have learned regarding periodic trends. DO NOT base your answer on tabulated values since exceptions may occur.|

germanium smallest
arsenic
selenium
bromine largest

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Electronegativity is the ability of an atom in a molecule to attract electrons to itself.

In general, electronegativity increases as the atomic radius decreases. Smaller atoms have higher electronegativities.

Notice that all of these elements are in row 4.

Across a row of the periodic table, atomic radius decreases with increasing atomic number. The electronegativity, therefore, increases.

The following table shows the actual radii and electronegativities for these elements. Please keep in mind that the actual values may sometimes deviate from the rule.

Element| Atomic Number| Radius (pm)| Electronegativity| germanium| 32| 122| 1.9|
arsenic| 33| 120| 2.1|
selenium| 34| 119| 2.4|
bromine| 35| 114| 2.8|
Bottom of Form

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2.Top of Form
Arrange the following elements in order of increasing electronegativity:

germanium, silicon, tin, carbon
Please answer this question according to the general rules you have learned regarding periodic trends. DO NOT base your answer on tabulated values since exceptions may occur.|

tin smallest
germanium
silicon
carbon largest

Feedback:
Electronegativity is the ability of an atom in a molecule to attract electrons to itself.

In general, electronegativity decreases as the atomic radius increases. Larger atoms have lower electronegativities.

Notice that all of these elements are in group 4A.

Within a group of the periodic table, atomic radius increases with atomic number. The electronegativity, therefore, decreases.

The following table shows the actual radii and electronegativities for these elements. Please keep in mind that the actual values may sometimes deviate from the rule.

Element| Atomic Number| Radius (pm)| Electronegativity| tin| 50| 140| 1.8|
germanium| 32| 122| 1.9|
silicon| 14| 118| 1.8|
carbon| 6| 77| 2.5|
Bottom of Form

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3.Top of Form
Arrange the following elements in order of increasing electronegativity:

bismuth, polonium, lead, astatine
Please answer this question according to the general rules you have learned regarding periodic trends. DO NOT base your answer on tabulated values since exceptions may occur.|

lead smallest
bismuth
polonium
astatine largest

Feedback:
Electronegativity is the ability of an atom in a molecule to attract electrons to itself.

In general, electronegativity increases as the atomic radius decreases. Smaller atoms have higher electronegativities.

Notice that all of these elements are in row 6.

Across a row of the periodic table, atomic radius decreases with increasing atomic number. The electronegativity, therefore, increases.

The following table shows the actual radii and electronegativities for these elements. Please keep in mind that the actual values may sometimes deviate from the rule.

Element| Atomic Number| Radius (pm)| Electronegativity| lead| 82| 146| 1.7|
bismuth| 83| 150| 1.8|
polonium| 84| 168| 1.9|
astatine| 85| 140| 2.1|

1. For each bond, use + and - to show the direction of polarity. Indicate by letter which bond is expected to be the most polar.

(A) + Se-O -

(B) + Se-S -

(C) - O-S +

The most polar bond is (A,B,C) A.

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When two atoms are joined by a covalent bond, the bond will have polar character when the electronegativities of the two atoms are different. The atom with the highest electronegativity will have a partial...
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