<span>I bet this is the notation used in nuclear reactions. The superscript represents the mass number while the subscript represents the atomic number of the element X. So, we find the element with an atomic number of 12. That would be Magnesium or Mg.</span>
Answer:
(1) atomic numbers
Explanation:
The observed regularities in the properties of the elements on the periodic table are periodic functions of their atomic numbers.
- Atomic number is the number of protons in an atom.
- The periodic law states that "the properties of elements are a periodic function of their atomic number".
- Elements on the periodic table are arranged based on the atomic numbers they contain.
- The number of positively charged particles in an atom is the atomic number.
Answer: A volume of 500 mL water is required to prepare 0.1 M 
from 100 ml of 0.5 M solution.
Explanation:
Given: 
= 0.1 M, 
= ?
= 0.5 M, 
= 100 mL
Formula used to calculate the volume of water is as follows.
Substitute the values into above formula as follows.
Thus, we can conclude that a volume of 500 mL water is required to prepare 0.1 M from 100 ml of 0.5 M solution.
Answer:
By using different techniques.
Explanation:
For example: Chromatography involves solvent separation on a solid medium. Distillation takes advantage of differences in boiling points. Evaporation removes a liquid from a solution to leave a solid material. Filtration separates solids of different sizes.
sourced from the internet
Answer:
Answer the following questions: What is the composition of air? Answer: Air is composed of nitrogen, oxygen, carbon dioxide, many other gases, water vapour and dust particles. Which gas in the atmosphere is essential for respiration?
Explanation:
