Mendeleev gave the name eka-aluminum to an A. compound containing aluminum. B. mixture of aluminum and an unknown element. C. un
known element he predicted would have properties similar to those of aluminum. D. rare isotope of aluminum.
2 answers:
Mendeleev gave the name eka-aluminum to an <u><em>C. unknown element he predicted would have properties similar to those of aluminum </em></u>
<h3>Further explanation </h3>The periodic system of elements is an arrangement of elements classified based on similar properties and their atomic number order.
The periodic system is divided into groups (vertical order) and periods (horizontal order)
There are some scientists who do the grouping of elements, mostly based on the relative atomic mass
- 1. Dobereiner
These scientists grouped the elements into groups of three elements called the Triade
- 2. Newlands
These scientists arrange elements based on their relative atomic mass increases called the octave law. Similarities between the elements occur in elements that have a difference of 1 octave (elements 1 and 8, elements 2 and 9, elements 3 and 10 etc.)
- 3. Mendeleev
These scientists group elements based on their relative atomic mass increases.
Mendeleev placed elements that have similar properties in one group (vertical direction) and based on the increase in relative atomic mass in one period
In the periodic system made by Mendeleev, there are some parts in the group that are left blank because the element has not been found but is predicted to have the same properties as the elements in that group.
The Mendeleev periodic system is useful after the discovery of new elements which had similar properties in accordance with Mendeleev's predictions.
In group III, under the Al element, Mendeleev empties the unknown element, but it is predicted to have similar properties with aluminum and is given the name eka-aluminum. This element was later discovered and named gallium (Ga) with atomic number 31 and relative atomic mass of 69.72
<h3>Learn more </h3>
electron affinity
Identify the group number in the periodic table
the charge on each ion in the compounds
Keywords: element, group, period, eka-aluminum, gallium, periodic system
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Answer:C
Explanation:
Given
Both ball are thrown simultaneously with same velocity
Suppose h be the height of roof and u be the initial velocity of balls
For ball thrown from room initial total energy is
Now this ball potential energy convert to kinetic energy and add up in available kinetic energy to give 100 J at bottom
For second ball, energy at bottom is equal to kinetic Energy of ball
Therefore this energy remains constant and only converts to Potential Energy as ball moves upward
but as soon as ball hit the ground energy will be less than 100 J because first ball has sum of Potential and Kinetic energy .