Answer:
<em><u>universal law of </u></em><em><u>gravitation</u></em>
Explanation:
According to Newton's law of gravitation, every particle in universe attracts every other particles with a force which is directly proportional to the product of their masses and inversely proportional to the square of distance between their centres!
Consider two particles having masses m1 and m2 and are apart r units, then the gravitational force acting between them is given by
Where G is universal gravitational constant or proportionality constant!!
<em><u>Thanks for joining brainly community!</u></em>
Answer: c. elements in the same row of the periodic table
Explanation: It kind of represents a graph of the periodic table
The answer is rubidium -91 because it takes a shorter time of 58.4 seconds to become stable.
The elements in which electrons are progressively filled in 4f-orbital are called lanthanoids.
There are 15 metallic chemical elements called lanthanoids.
Those elements are with atomic numbers from 57 to 71.
Lanthanoids belong to f-block elements because of the filling of the 4f-orbitals.
One of the lanthanoids, lutetium (chemical symbol Lu) has 14 electrons if 4f orbitals.
Electron configuration of lutetium: [Xe] 4f14 5d1 6s2
f-orbitals are similar to the d orbital, but cut in half (eight lobes instead of four).
Lanthanoids are used not as materials in catalysts, alloys, lasers and cathode-ray tubes.
More info about lanthanoids: brainly.com/question/24413965
#SPJ4
