The first attempt to classify elements into triads was made by:
A.
Henry Moseley (1913) — who used X-ray spectra to determine atomic numbers
B.
Johann Wolfgang Döbereiner (1829) — he grouped elements into 'triads' where the atomic weight of the middle element was approximately the arithmetic mean of the other two
C.
Dmitri Mendeleev (1869) — who arranged elements in order of atomic mass
D.
John Alexander Newlands (1865) — who proposed the Law of Octaves
B. Johann Wolfgang Döbereiner (1829) — he grouped elements into 'triads' where the atomic weight of the middle element was approximately the arithmetic mean of the other two
2.
Newlands' Law of Octaves (1865) stated that:
A.
When elements are arranged in increasing order of atomic weights, every eighth element has properties similar to the first, like the eighth note in a musical octave
B.
Elements can be classified into groups of three with the middle element's mass being the mean of the other two
C.
Properties of elements are a periodic function of their atomic numbers
D.
Elements in the same vertical column have identical physical and chemical properties
A. When elements are arranged in increasing order of atomic weights, every eighth element has properties similar to the first, like the eighth note in a musical octave
3.
Mendeleev's Periodic Law (1869) states that:
A.
The chemical properties of elements depend only on the number of electrons
B.
The physical and chemical properties of elements are a PERIODIC FUNCTION of their ATOMIC WEIGHTS (atomic masses)
C.
Properties of elements are periodic functions of their atomic numbers
D.
Elements in the same group always have the same atomic mass
B. The physical and chemical properties of elements are a PERIODIC FUNCTION of their ATOMIC WEIGHTS (atomic masses)
4.
What was the most significant MERIT of Mendeleev's Periodic Table?
A.
He predicted the existence and properties of undiscovered elements (eka-boron, eka-aluminium, eka-silicon) which were later discovered (Sc, Ga, Ge respectively) with properties matching his predictions
B.
He placed isotopes of the same element in different groups based on their mass
C.
He arranged all 92 naturally occurring elements correctly without any anomalies
D.
He correctly explained why atomic mass was more fundamental than atomic number
A. He predicted the existence and properties of undiscovered elements (eka-boron, eka-aluminium, eka-silicon) which were later discovered (Sc, Ga, Ge respectively) with properties matching his predictions
5.
Which pair of elements was placed by Mendeleev in an ORDER OPPOSITE to their atomic masses? (A major anomaly of his table)
A.
Sodium (Na) placed before Potassium (K)
B.
Tellurium (Te, At.Wt.=127.6) placed before Iodine (I, At.Wt.=126.9) — Te has higher atomic mass but is placed before I
