What's in an atom?
- Atoms contain a nucleus and a lot of empty space
- In the empty space, there are electrons
- Atomic number is determined by the number of protons in the nucleus
- Mass number (atomic mass) is determined by the number of protons PLUS neutrons in the nucleus
- The atomic number and mass number are written in atomic notation as:
Examples
How many protons are there inside an atom of Cl?
According to the periodic table, chlorine is the 35th element, and so it has 35 protons.
What is the atomic notation of an atom with 19 protons and 20 neutrons?
19 protons = potassium = symbol "K"
Mass number = Protons + Neutrons = 19 + 20 = 39
Therefore the atomic notation is:
According to the periodic table, chlorine is the 35th element, and so it has 35 protons.
What is the atomic notation of an atom with 19 protons and 20 neutrons?
19 protons = potassium = symbol "K"
Mass number = Protons + Neutrons = 19 + 20 = 39
Therefore the atomic notation is:
Video Lesson
I have created this video about it if you are looking for a brief review.
