Atomic Number Chemistry Example 1
Follow the full solution, then compare it with the other examples linked below.
Example 1
easyElement X has 15 protons. Identify the element and determine the number of electrons in a neutral atom.
Solution
- 1 Look up atomic number on the periodic table: this corresponds to phosphorus (P).
- 2 The number of protons equals the atomic number, so phosphorus has 15 protons in its nucleus.
- 3 A neutral atom carries no net charge, meaning the number of electrons equals the number of protons: 15 electrons.
Answer
The atomic number uniquely defines each element and equals the number of protons. In a neutral atom, the electron count matches the proton count.
About Atomic Number
The number of protons in an atom's nucleus, which uniquely identifies the element and determines its position in the periodic table.
Learn more about Atomic Number →More Atomic Number Examples
Example 2 medium
Two atoms both have a mass number of 40. Atom A has 20 protons and Atom B has 19 protons. Are they t
Example 3 easyWhat is the atomic number of an element with 29 protons? Name the element.
Example 4 easyAn atom has atomic number 15. How many protons does it have? If the atom is neutral, how many electr