Chapter 4.8, Problem 4.87QAP

Interpretation Introduction

Interpretation:

The different character of an element can be predict from its position in the periodic table.

Concept Introduction:

• Metallic character: The tendency of an element to leave electron from its outer shell to form cation is called its electropositivity which is parallel to its metallic property. Thus the element which can leave electron easily have more metallic property. The metallic character of the elements in a group increases as I.P. decreases.

• Number of protons: For a neutral atom the number of electron is equivalent to the number of proton present in the nucleus.

• Prevalent Isotope: The most prevalent isotope is the most abundant isotope of a particular element in nature.

• In the definition of atomic mass, the average word has been used. It is due to the use of mass spectrometer to determine the mass of a substance. It was observed that most elements consists of atoms of more than one mass i.e. they exist in the form of isotopes. To determine the abundance and specific mass of isotope the popular method is weighted average mass method.

• The weighted average mass method: Let consider one element A has n-number of isotopes. Then as per weighted average mass method, the mass of the element is =

$\text{(}{}^{\text{A}}\text{M}{\text{ass}}_{\text{Isotope1}}\text{ × }{}^{\text{A}}\text{A}{\text{bundance}}_{\text{Isotope 1}}\text{ ) + (}{}^{\text{A}}\text{M}{\text{ass}}_{\text{Isotope 2}}\text{ × }{}^{\text{A}}\text{A}{\text{bundance}}_{\text{Isotope 2}}\text{ ) + }\mathrm{......}\text{(}{}^{\text{A}}\text{M}{\text{ass}}_{\text{Isotope n}}\text{ × }{}^{\text{A}}\text{A}{\text{bundance}}_{\text{Isotope n}}\text{ )}$

Given:

e) Potassium has three naturally occurring isotopes K-39 (93.26%, 38.964 amu), K-40 (0.0117%, 39.964 amu), K-41 (6.73%, 40.962 amu).

Interpretation Introduction

To determine:

a)

The name of group and group number that contains potassium.