Periodic Table Trends

The periodic law states that:

• The periodic table arranges elements into periods and groups.

• The properties of elements recur periodically based on their metallic qualities.

• The properties of elements recur periodically when arranged by increasing atomic mass.

• The properties of elements recur periodically when arranged by increasing atomic number.

When atoms react, they often lose, gain, or share electrons to form a more stable version of themselves. For example, alkali metals such as Na lose their outer shell electron in their reactions to form compounds. The electron configuration of alkali metals would then resemble those of which group of the periodic table in the compounds they form?

• A

• 2A

• 7A

• 8A

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In the periodic table hydrogen is placed in Group 1A and helium is placed in Group 8A. The most likely reason for this is: 

• Hydrogen has one outer shell electron and helium has a full outer shell of electrons.

• Hydrogen has one outer shell electron and helium has 8 electrons in its outer shell.

• Hydrogen and helium are both metals.

• Hydrogen and helium are both gases.

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The metallic character of elements _____ across a period. Metals are good conductors of ______.

• increases; electricity

• decreases; heat

• decreases; metalloids

• remains the same; luster

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Which statements are true concerning elements in the same group of the periodic table? 

• They have similar periodic properties and the same outer shell electron configuration.

• They are all metals or nonmetals, but not both.

• They are either all solids or all liquids or all gases.

• They have the same number of shells of electrons.

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The valence electrons of an atom do not experience the full attractive force of protons in the atom’s nucleus due to the presence of inner core electrons. The reduction in nuclear charge experienced by valence electrons due to inner core electrons is called the 

• ionization energy effect.

• nuclear charge effect.

• periodic law effect.

• shielding effect.

The effective nuclear charge, Zeff, experienced by valence electrons in an atom can be estimated from the equation:

Zeff = the number of protons – the number of core electrons

Using this estimation, effective nuclear charge for Main Group elements would ___ left to right across a period and ___ down a group. 

Which option correctly completes the blanks in the statement?

• increase; decrease

• increase; remain the same

• decrease; remain the same

• remain the same; remain the same

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A Main Group element has 81 protons and an estimated effective nuclear charge of +3. Therefore, the element has ___ core electrons and can be found in Group ___ of the Periodic Table.

Which set correctly completes the blanks?

• 84, 3A

• 81, 5A

• 78, 3A

• 78, 5A

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The diagram shows the electron structures of two alkali metals and two halogens. When these elements react and form compounds, alkali metals lose their one valence electron while halogens gain one additional electron to their valence shell. The vigor of the reaction is directly related to the distance of the valence electrons from the attractive pull of the atom’s nucleus. For alkali metals, it becomes easier to lose the valence electron with increasing distance of that electron from the attractive pull of the nucleus. For halogens, it becomes easier to gain an additional electron to the valence shell with decreasing distance of that shell to the attractive pull of the atom’s nucleus.

For the given elements, which reaction will proceed most quickly or be the easiest?

• Li and F

• Li and Cl

• Na and F

• Na and C

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Which of the following correctly completes the statement:

Cations are always _____ than the parent atom and anions are always _____ than the parent atom.    

• smaller; smaller

• larger; smaller

• smaller; larger

• larger; larger