What part of chemistry is this
Answer:
Chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. These processes are called chemical reactions and, in general, are not reversible except by further chemical reactions.
Explanation:
Answer:
The symbol of each element is, Ne, Na, Mg, and Al.
Explanation:
Below is the list of elements that has an atomic mass of less than 19.3 u.
The atomic mass of Neon is 20.1797 u and the atomic number is 10.
The atomic mass of Sodium is 22.989769 u and the atomic number is 11.
The atomic mass of Magnesium is 24.305 u and the atomic number is 12.
The atomic mass of Aluminium is 26.981539 u and the atomic number is 13.
Here, the symbol of each element is, Ne, Na, Mg, and Al.