Question

Which of the following Statements are NOT true about the periodic table? 
A. The properties of elements are a function of atomic weights. 
B. The properties of elements are a function of atomic numbers. 
C. Elements having similar outer electronic configuration are arranged in the same period. 
D. An element's location reflects the quantum numbers of the last filled orbital. 
E. The number of elements in a period is the same as the number of atomic orbitals available in the energy level that is being filled.

• A. A, C, and E Only
• B. D and E Only
• C. A and E Only
• D. B, C, and E Only

Hint:

Remember, elements in the same period have the same principal quantum number, and elements in the same group have the same outer electronic configuration. The modern periodic table is based on atomic number, not atomic weight.

Answer 1

The Correct Option is A

To identify the inaccuracies regarding the periodic table, each statement will be individually assessed:

1. A. The properties of elements are a function of atomic weights.
   • This statement aligns with Dmitri Mendeleev's initial periodic law, which ordered elements by increasing atomic weight. However, this has been superseded by atomic number ordering to resolve discrepancies.
   • Therefore, this statement is inaccurate based on the current periodic law, which defines elements' properties as a periodic function of their atomic numbers.
2. B. The properties of elements are a function of atomic numbers.
   • This statement is accurate, reflecting the modern periodic law established by Henry Moseley, which orders elements by increasing atomic number and rectifies issues present in Mendeleev's system.
3. C. Elements having similar outer electronic configuration are arranged in the same period.
   • Elements with similar outer electronic configurations are grouped together in the same group, not the same period.
   • Consequently, this statement is inaccurate.
4. D. An element's location reflects the quantum numbers of the last filled orbital.
   • This statement is accurate. An element's position on the periodic table is determined by the quantum numbers, specifically the principal quantum number (n) and azimuthal quantum number (l), of its outermost electron's orbital.
5. E. The number of elements in a period is the same as the number of atomic orbitals available in the energy level that is being filled.
   • The quantity of elements in a period corresponds to the total electron capacity of the orbitals within that energy level, not the count of individual atomic orbitals.
   • For instance, the first period contains 2 elements due to the 1s orbital's capacity, while the second period has 8 elements, accounting for the 2s and 2p orbitals.
   • This statement is inaccurate.

Based on this evaluation, statements A, C, and E are incorrect according to the contemporary understanding of the periodic table.