1. Decreases by 4. (B)
2. The atomic number changes. (B)
3. 56/26 Fe. (C)
4. Potassium-40;t1/2=25 days. (B)
5. Takes place in the upper atmosphere. (A)
Answer:
Explanation:
Density is m/V. Also, 1 liter = 1000 
. So, we get 0.890/(5*1000) = 
g/cm^3. You can convert this to kg/m^3 as well by multiplying it by 10. Depends which one you want.
6 moles to equal that I do t know for sure though
MgCl2 is an ionic compound because chemical bonds in the molecule are formed by the transfer of electrons among Mg and Cl atoms.
<h3>What is chemical bond ?</h3>
A chemical bond is a strong bond that can be formed between atoms, ions, or molecules to create chemical compounds. The bond may be created by the sharing of electrons in covalent bonds or by the electrostatic attraction of two oppositely charged ions, as in ionic bonds. Covalent, ionic, and metallic bindings are examples of "strong bonds" or "primary bonds," whereas dipole-dipole interactions, the London dispersion force, and hydrogen bonding are examples of "weak bonds" or "secondary bonds."
The positively charged protons in the nucleus and the negatively charged electrons in its orbit are attracted to one another by the basic electromagnetic force.
To learn more about chemical bonds from the given link:
brainly.com/question/819068
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