Beryllium has 4 electrons.
Answer: The metric system is a system of measurement that uses the meter, liter, and gram as base units of length (distance), capacity (volume), and weight (mass) respectively. To measure smaller or larger quantities, we use units derived from the metric units.
Answer:
1.
First of all, let's convert the energy of the absorbed photon into Joules:
The energy of the photon can be rewritten as:
where
h is the Planck constant
c is the speed of light
is the wavelength of the photon
Re-arranging the formula, we can solve to find the wavelength of the absorbed photon:
2. 1.24 eV
In this case, when the electron jumps from the n=4 level to the n=3 level, emits a photon with wavelength
So the energy of the emitted photon is given by the formula used previously:
and using
we find
converting into electronvolts,
Explanation:
Researchers have shown that when really small particles are close to each other like in a nebula, they are attracted to each other due to electromagnetism (from static electricity) since the masses are too small for gravity to really matter. However, the answer is probably gravity, electromagnetism only played a small role in the very beginning when nothing had enough mass. After that, gravity caused everything to condense and gravity did a better job once everything had enough mass for gravity to matter.
I hope this helps, let me know if anything is unclear in the comments.
