The electron travels in circular orbits around the nucleus. The orbits have quantized sizes and energies. Energy is emitted from the atom when the electron jumps from one orbit to another closer to the nucleus.

atom: The smallest possible amount of matter which still retains its identity as a chemical element, consisting of a nucleus surrounded by electrons.

Metals atoms have loose electrons in the outer shells, which form a ‘sea’ of delocalised or free negative charge around the close-packed positive ions. These loose electrons are called free electrons. They can move freely throughout the metallic structure.

Solution : Electrons revolve around the nucleus in fixed orbits or shells called energy levels. Electrons rotate around the nucleus in one or more energy levels.

A calculation shows that the electron is traveling at about 2,200 kilometers per second. That’s less than 1% of the speed of light, but it’s fast enough to get it around the Earth in just over 18 seconds. Read up on what happens when nothing can go faster than the speed of light.

Outer space is teaming with fields and particles, as depicted in this artistic rendering. Even a “perfect” vacuum would still hold vacuum energy, the Higgs field, and spacetime curvature. Space seems empty to humans because we can’t see most of the stuff there, and because there is much less air than we are used to.

As long as the amount of stuff doesn’t go over a critical threshold, the universe will continue to expand forever, and eventually suffer heat death, freezing out. But if there’s too much stuff, the expansion of the universe will slow down and stop. Then the universe will begin to contract.

Kepler-452b (a planet sometimes quoted to be an Earth 2.0 or Earth’s Cousin based on its characteristics; also known by its Kepler Object of Interest designation KOI-7016.01) is a super-Earth exoplanet orbiting within the inner edge of the habitable zone of the Sun-like star Kepler-452, and is the only planet in the …

A common definition of space is known as the Kármán Line, an imaginary boundary 100 kilometers (62 miles) above mean sea level.

The universe (Latin: universus) is all of space and time and their contents, including planets, stars, galaxies, and all other forms of matter and energy. At the largest scale, galaxies are distributed uniformly and the same in all directions, meaning that the universe has neither an edge nor a center.