Interpretation: The reason for placement of argon before potassium in spite of its greater atomic mass and the
Concept Introduction:
Periodic Table: The available chemical elements are arranged considering their
In periodic table the horizontal rows are called periods and the vertical column are called group.
In periodic table the horizontal rows are called periods and the vertical column are called group. There are seven periods and 18 groups present in the table and some of those groups are given particular name as follows,
Atomic Number: Atomic number of the element is equal to the number of protons present in the nucleus of the element which is denoted by symbol Z. The superscript presents on the left side of the
Atomic mass: It is generally expressed in terms of atomic mass unit
Mass number: It is given by the total number of protons and the neutrons present in the nucleus of the element and it is denoted by symbol A. The subscript that lies on the left side of the symbol of the element represents the mass number.
Explanation of Solution
The reason that supports the placement of
Analyze the position of argon and potassium in the periodic table.
Examining the periodic table shows that argon is placed before the potassium irrespective of high atomic mass of
The average atomic mass of
Determine the average atomic mass for the given elements.
The average atomic mass for the given elements is obtained by addition of individual atomic mass of the isotopes multiplied with their percent abundance of the respective isotope.
Therefore, the average atomic mass for argon is
The reason that support the position of argon before potassium and the average atomic mass of the element is determined by using the atomic number, atomic mass and the abundance of the isotopes for the element.
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Chapter 8 Solutions
Chemistry
- Boron, atomic number 5, occurs naturally as two isotopes, 10B and 11B, with natural abundances of 19.9% and 80.1%, respectively. (a) In what ways do the two isotopes differ from each other? Does the electronic configuration of 10B differ from that of 11B? (b) Draw the orbital diagram for an atom of 11B. Which electrons are the valence electrons? (c) Indicate three ways in which the 1s electrons in boron differ from its 2s electrons. (d) Elemental boron reacts with fluorine to form BF3, a gas. Write a balanced chemical equation for the reaction of solid boron with fluorine gas. (e) ΔHf° for BF3(g) is -1135.6 kj/mol. Calculate the standard enthalpy change in the reaction of boron with fluorine. (f) Will the mass percentage of F be the same in 10BF3 and 11BF3? If not, why is that the case?arrow_forwardArrange in order of increasing nonmetallic character. (a) the period 4 elements Ga, Ge, Ti (b) the Group 5A elements P, Bi, and Narrow_forwardArrange in order of increasing nonmetallic character (a) the Period 3 elements P, Cl, and Na(b) the Group 7A elements F, Br, and Clarrow_forward
- Use the data from Appendix F to graph the variation ofatomic radius with atomic number for the rare-earth elements from lanthanum to lutetium.(a) What is the general trend in these radii? How do you account for it?(b) Which two elements in the series present exceptions to the trend?arrow_forwardUntil the early 1960s, the group 8A elements were calledthe inert gases. (a) Why was the term inert gases dropped?(b) What discovery triggered this change in name? (c) Whatname is applied to the group now?arrow_forwardThe elements of a period in the periodic table are given below in order from left to right: 3Li 4Be 5B 6C 80 (1) To which period do these elements belong? (11) Which of them will have the largest atomic radius. Explain the trend.arrow_forward
- Boron, atomic number 5, occurs naturally as two isotopes, 10B and 11B, with natural abundances of 19.9% and 80.1%, respectively.(a) In what ways do the two isotopes differ from each other? Does the electronic configuration of 10B differ from that of 11B? (b) Drawthe orbital diagram for an atom of 11B. Which electrons are the valence electrons? (c) Indicate three ways in which the 1s electrons inboron differ from its 2s electrons. (d) Elemental boron reacts with fluorine to form BF3, a gas. Write a balanced chemical equation forthe reaction of solid boron with fluorine gas. (e) ΔHf° for BF31g2 is -1135.6 kJ>mol. Calculate the standard enthalpy change in thereaction of boron with fluorine. (f) Will the mass percentage of F be the same in 10BF3 and 11BF3? If not, why is that the case?arrow_forwardArrange in order of increasing nonmetallic character. (Use the appropriate <, =, or > symbol to separate substances in the list.) (a) the Period 4 elements V, Ge, and K (b) the Group 5A elements N, As, and Bi Arrange in order of increasing atomic size. (Use the appropriate <, =, or > symbol to separate substances in the list.) (a) the Period 3 elements Mg, Si, and Ar (b) the Group 2A elements Ca, Ba, and Srarrow_forward25) Which of the following elements has the highest ionization energy? Ca Al Ne Ba Clarrow_forward
- (a) Use orbital diagrams to illustrate what happens when anoxygen atom gains two electrons. (b) Why does O3 - not exist?arrow_forwardArrange in order of increasing ionization energy. (a) the Group 1A elements H, Li, and Cs (b) the Period 4 elements As, K, & Searrow_forwardAssuming that the seventh period of the periodictable has 32 members, what should be the atomicnumber of (a) the noble gas following radon (Rn);(b) the alkali metal following francium (Fr)?arrow_forward
- Chemistry: Principles and PracticeChemistryISBN:9780534420123Author:Daniel L. Reger, Scott R. Goode, David W. Ball, Edward MercerPublisher:Cengage Learning