The answer to this question would be: <span>D. Magnesium
The </span><span>number of energy levels of aluminum is 3 which was why it was put on the 3rd row. The valence of calcium is 2 which is why it was put in the 2nd column. If you look at the periodic table, the answer should be clear that it was magnesium.</span>
Answer:
Increase
Explanation:
If temperature is held constant, the equation is reduced to Boyle's law. Therefore, if you decrease the pressure of a fixed amount of gas, its volume will increase.
The answer is c. hydrogen is flammable and dangerous
Answer:
1. 
2. 
Explanation:
An ion is formed when an atom that is said to be neutral gains or losses electrons.
It is thought that a negative ion (anion) is produced as it gains electrons and a positive ion (cation) is formed when it loses an electron.
Atomic number is the total number of protons and electrons in a neutral atom.
From the information
Protons = 14
electron = 18
Net Charge = no of proton - no of electron
= 14 - 18 = -4
Mass number = 14 + 15 = 29
Thus, the chemical symbol = 
For ion with 27 proton, 32 neutrons and 25 electrons
Net charge = 27 - 25 = +2
Mass number = 27 + 32 = 59
Thus, the chemical symbol = 