Chemical formulas are used to describe the types of atoms and their numbers in an element or compound. The atoms of each element are represented by one or two different letters. When more than one atom of a specific element is found in a molecule, a subscript is used to indicate this in the chemical formula.
A covalent bond means shared electrons between atoms. This is similar to kids sharing markers because the markers (electrons) are being shared between the kids (atoms). Covalent bonds are different than this metaphor because 1) the electrons are constantly moving about while the kids can steal and keep the markers and 2) the electrons and atoms are physically smaller
Answer:
The speed of an electron is 0.01908 m/s.
Explanation:
De-Broglie wavelength is given by:

where,
= wavelength of a particle
h = Planck's constant = 
m = mass of particle
v = velocity of the particle
Velocity of an electron = v
Mass of an electron = 
Wavelength of electron is twice the displacement in seconds which is velocity of an electron.
Then.wavelength of an electron = 

v = 0.01908 m/s
The speed of an electron is 0.01908 m/s.
Answer:
half-life = 3.8 days
total time of decay = 15.2 days
initial amount = 100. g
number of half-lives past: 15.2/3.8 = 4 half-lives
4 half-lives = 1/16 remains
100. g x 1/16 = 6.25 g
Yes they can have origins in nature. A bunch of the elements on the periodic table are chemicals and this are basic substances and cannot be man made.