Question

1. what was a limitation of the law of octaves? a. it worked only for heavier elements b. it worked only for noble gases c. it worked only for light elements d. it predicted too many elements

part ii: true or false (10 items) write t if the statement is true and f if false.

1. the law of triads grouped elements in threes based on similar atomic mass.
2. mendeleev arranged elements by increasing atomic number.
3. the law of octaves failed beyond the element calcium.
4. periodic law explains repeating chemical properties among elements.
5. mendeleev did not leave gaps for undiscovered elements.
6. group elements in the periodic table share similar properties.
7. the law of triads applies to all known elements.
8. mendeleevs periodic table was accepted because it predicted unknown elements.

Explanation:

1. The Law of Triads grouped elements in threes based on similar atomic mass, so this statement is True (T).
2. Mendeleev arranged elements by increasing atomic mass, not atomic number (Moseley later related properties to atomic number), so this statement is False (F).
3. The Law of Octaves failed beyond calcium as it couldn't account well for heavier elements, so this statement is True (T).
4. The Periodic Law indeed explains repeating chemical properties among elements, so this statement is True (T).
5. Mendeleev left gaps for undiscovered elements, so this statement is False (F).
6. Group elements in the periodic table share similar properties due to having the same number of valence - electrons, so this statement is True (T).
7. The Law of Triads does not apply to all known elements, only to some groups of three, so this statement is False (F).
8. Mendeleev's periodic table was accepted because it predicted unknown elements, so this statement is True (T).

For the multiple - choice question, the Law of Octaves worked only for light elements. So the answer is C.

Answer:

1. T
2. F
3. T
4. T
5. F
6. T
7. F
8. T
9. C. It worked only for light elements