A positively charged subatomic particle found in the nucleus of every atom, with a charge of +1 and a mass of approximately 1 atomic mass unit (amu).
The identity badge of an atom—how many protons determines what element it is.
Showing a random 20 of 50 problems.
Example 1
medium
If element X has 24 protons, in what group of the periodic table does it sit?
Example 2
medium
Which has more protons: Fe2+ or neutral Fe?
Example 3
medium
An ion has 17 protons and 18 electrons. What is its net charge?17 protons, 18 electrons → net charge −1
Example 4
medium
The mass of a single proton is approximately 1.673×10−24 g. How many protons would it take to have a combined mass of 1 g?
Example 5
medium
Two atoms each have 6 protons. One has 6 neutrons, the other 8. What stays the same, and what differs?
Example 6
easy
True or false: the number of protons equals the atomic number.
Example 7
easy
About what fraction of the atom's mass is contributed by protons (and neutrons)?
Example 8
easy
How many protons does an atom with atomic number Z=8 have?
Example 9
challenge
Why does adding one proton to a nucleus change the element, but adding one neutron does not?
Example 10
medium
An atom of element X has 15 protons, 16 neutrons, and 15 electrons. What is X?
Example 11
easy
In which part of the atom are protons found?
Example 12
medium
An isotope 31P has 16 neutrons. How many protons does it have?
Example 13
easy
What is the charge in coulombs of a single proton?
Example 14
medium
Carbon-14 undergoes beta decay. What element does it become?
Example 15
easy
An atom has 13 protons. What element is it?
Example 16
hard
A nucleus has mass number 40 and atomic number 20. Identify the element and give its proton count.
Example 17
medium
Atom 1 has 7 protons; atom 2 has 8 protons. Are they the same element? Explain in one line.
Example 18
challenge
Element X has atomic number 26. An X atom loses 3 electrons. State its proton count, the ion charge, and the element name.
Example 19
easy
Can protons be gained or lost during an ordinary chemical reaction?
Example 20
medium
An atom has a mass number of 19 and contains 10 neutrons. How many protons does it have, and what element is it?Mass number 19, 10 neutrons → 9 protons: fluorine