Hello!
Each element on the periodic table ALWAYS begins with an UPPERCASE letter, for example, hydrogen is written as H.
If the element has two letters, for example lithium, then the first letter is UPPERCASE, and the next letter is LOWERCASE. This is shown as Li.
If there's two or more elements (also known as a compound), (ex. sodium chloride), then it follows the same rules, the first letter is in UPPERCASE and next letter is LOWERCASE, but when a new element is introduced (in this case chlorine), the first letter is UPPERCASE and the next letter in LOWERCASE. Sodium is Na and Chlorine is Cl. As a compound it is NaCl, and it's name is sodium chloride.
Basic rules:
- First letter of any element is UPPERCASE
- Second letter of any element is LOWERCASE
- If it is a compound, then each different element follows the rules like 1 and 2
