Chapter 3, Problem 27E

Interpretation Introduction

(a)

Interpretation:

The element $\text{H}$ is to be classified as a metal, nonmetal, or semimetal.

Concept introduction:

An element is a substance that cannot be broken down into any smaller units. An element can be classified as metal, nonmetal or metalloid. The elements in a modern periodic table are arranged in an increasing order of their atomic number. In this modern periodic table, the horizontal rows are said to be periods and vertical columns are said to be groups. There are seven periods and eighteen groups in a modern periodic table.

Answer to Problem 27E

The element hydrogen $\left(\text{H}\right)$ is classified as a nonmetal.

Explanation of Solution

In the periodic table, the metals are arranged on the left of the periodic table, the nonmetals are arranged on the right of the periodic table and the semimetals are arranged in between the metals and nonmetals.

The elements which have metallic luster, high electro-positivity, have high thermal and electrical conductivities and high malleability and ductility are classified as metals.

The elements which are brittle exist in powdery solids or gaseous form; have high electronegativity and the properties opposite to that of metals are classified as nonmetals.

The elements having properties in between of metals and nonmetals are classified as semimetals.

Hydrogen $\left(\text{H}\right)$ has atomic number $1$. It is placed on the top and at the left of the periodic table. Therefore, it should be a metal but there is an exception with hydrogen and it has the properties more similar to nonmetals. Thus, hydrogen $\left(\text{H}\right)$ is a nonmetal.

Conclusion

The element hydrogen $\left(\text{H}\right)$ is classified as a nonmetal.

Interpretation Introduction

(b)

Interpretation:

The element $\text{He}$ is to be classified as a metal, nonmetal, or semimetal.

Concept introduction:

An element is a substance that cannot be broken down into any smaller units. An element can be classified as metal, nonmetal or metalloid. The elements in a modern periodic table are arranged in an increasing order of their atomic number. In this modern periodic table, the horizontal rows are said to be periods and vertical columns are said to be groups. There are seven periods and eighteen groups in a modern periodic table.

Answer to Problem 27E

The element helium $\left(\text{He}\right)$ is classified as a nonmetal.

Explanation of Solution

In the periodic table, the metals are arranged on the left of the periodic table, the nonmetals are arranged on the right of the periodic table and the semimetals are arranged in between the metals and nonmetals.

The elements which have metallic luster, high electro-positivity, have high thermal and electrical conductivities and high malleability and ductility are classified as metals.

The elements which are brittle exist in powdery solids or gaseous form; have high electronegativity and the properties opposite to that of metals are classified as nonmetals.

The elements having properties in between of metals and nonmetals are classified as semimetals.

Helium $\left(\text{He}\right)$ has an atomic number of $2$. It is placed on the top at the right of the periodic table and it has the properties more similar to nonmetals. Thus, helium $\left(\text{He}\right)$ is a nonmetal.

Conclusion

The element helium $\left(\text{He}\right)$ is classified as a nonmetal.

Interpretation Introduction

(c)

Interpretation:

The element $\text{Hf}$ is to be classified as a metal, nonmetal, or semimetal.

Concept introduction:

An element is a substance that cannot be broken down into any smaller units. An element can be classified as metal, nonmetal or metalloid. The elements in a modern periodic table are arranged in an increasing order of their atomic number. In this modern periodic table, the horizontal rows are said to be periods and vertical columns are said to be groups. There are seven periods and eighteen groups in a modern periodic table.

Answer to Problem 27E

The element hafnium $\left(\text{Hf}\right)$ is classified as a metal.

Explanation of Solution

In the periodic table, the metals are arranged on the left of the periodic table, the nonmetals are arranged on the right of the periodic table and the semimetals are arranged in between the metals and nonmetals.

The elements which have metallic luster, high electro-positivity, have high thermal and electrical conductivities and high malleability and ductility are classified as metals.

The elements which are brittle exist in powdery solids or gaseous form; have high electronegativity and the properties opposite to that of metals are classified as nonmetals.

The elements having properties in between of metals and nonmetals are classified as semimetals.

Hafnium $\left(\text{Hf}\right)$ has an atomic number of $72$. It is placed at the left of the periodic table and it has the properties more similar to metals. Thus, hafnium $\left(\text{Hf}\right)$ is a metal.

Conclusion

The element hafnium $\left(\text{Hf}\right)$ is classified as a metal.

Interpretation Introduction

(d)

Interpretation:

The element $\text{Ho}$ is to be classified as a metal, nonmetal, or semimetal.

Concept introduction:

An element is a substance that cannot be broken down into any smaller units. An element can be classified as metal, nonmetal or metalloid. The elements in a modern periodic table are arranged in an increasing order of their atomic number. In this modern periodic table, the horizontal rows are said to be periods and vertical columns are said to be groups. There are seven periods and eighteen groups in a modern periodic table.

Answer to Problem 27E

The element holmium $\left(\text{Ho}\right)$ is classified as a metal.

Explanation of Solution

In the periodic table, the metals are arranged on the left of the periodic table, the nonmetals are arranged on the right of the periodic table and the semimetals are arranged in between the metals and nonmetals.

The elements which have metallic luster, high electro-positivity, have high thermal and electrical conductivities and high malleability and ductility are classified as metals.

The elements which are brittle, exist in powdery solids or gaseous form, have high electronegativity and the properties opposite to that of metals are classified as nonmetals.

The elements having properties in between of metals and nonmetals are classified as semimetals.

Holmium $\left(\text{Ho}\right)$ has an atomic number of $67$. It is placed in the section of inner transition metals in the periodic table and it has the properties more similar to metals. Thus, holmium $\left(\text{Ho}\right)$ is a metal.

Conclusion

The element holmium $\left(\text{Ho}\right)$ is classified as a metal.