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Answer the following about the characteristics of the elements in Group 1(the alkali metals). 1....

Question:

Answer the following about the characteristics of the elements in Group 1(the alkali metals).

1. How do they react with bromine?

A. a salt is formed (MBr_2)

B. a salt is formed (MBr)

C. no reaction

2. How do they react with water?

A. hydrogen gas is released

B. no reaction

3. How do they react with oxygen?

A. an oxide is formed (M_2O)

B. an oxide is formed (MO)

C. no reaction

4. Which reacts the most vigorously?

A. Li

B. Na

C. K

D. Rb

E. Cs

5. Which element in the group exhibits different chemistry from the others?

A. Li

B. Na

C. K

D. Rb

E. Cs

Group 1 Elements:

The elements in group 1 of the periodic table represent the alkali metals ( Li, Na, K, Rb, Cs, and Fr).

They have just one electron in the outermost shell, which can be lost easily to attain the nearest noble gas configuration.

Answer and Explanation: 1

1. The valency of alkali metals is one. Also, the valency of bromine is one.

While writing the chemical formula of a compound between two atoms, the valencies are inter-crossed.

Alkali metals combine with bromine to form bromides with the chemical formula MBr.

Thus, option (B) is the correct answer.

_____

2. Alkali metals react with water to form the corresponding hydroxides and release hydrogen gas.

{eq}2M+2H_{2}O\rightarrow 2MOH+H_{2} {/eq}

Thus, option (A) is the correct answer.

_____

3. Alkali metals react with oxygen to form corresponding oxides. Lithium forms {eq}Li_{2}O {/eq}, sodium forms dioxide NaO and other alkali metals form super-oxide {eq}(MO_{2}) {/eq}

Thus, both options (A) and (B) are correct.

_____

4. Lithium reacts with water most vigorously. This is because of its very small size, a large number of water molecules surrounds the lithium ions and thus the enthalpy of hydration is thus the highest.

Option (A) is thus the correct answer.

_____

5. Lithium in the alkali metal group has an exceptionally small size and large size/charge ratio and thus behaves differently than the other elements of the group. This is called the anomalous behavior.

Option (A) is thus the correct answer.


Learn more about this topic:

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Alkali Metals (Group 1A Elements): Definition & Properties

from

Chapter 7 / Lesson 2
28K

Learn about the alkali metals group and explore the group 1A elements. Understand their charge, valence electrons, ions, and find out whether they are soft or hard.


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