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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- Force=700N
- Acceleration=9.8m/s^2
Using newtons law
Answer:
The speed of the ambulance is 4.30 m/s
Explanation:
Given:
Frequency of the ambulance, f = 1790 Hz
Frequency at the cyclist, f' = 1780 Hz
Speed of the cyclist, v₀ = 2.36 m/s
let the velocity of the ambulance be 'vₓ'
Now,
the Doppler effect is given as:
where, v is the speed of sound
since the ambulance is moving towards the cyclist. thus, the sign will be positive
thus,
on substituting the values, we get
or
vₓ = 4.30 m/s
Hence, <u>the speed of the ambulance is 4.30 m/s</u>