the atomic number of an element is equal to the..?

The number of protons

The atomic number of an element is equal to the number of protons in the nucleus.

atomic number = no. of electrons = no. of protons

The atomic number of an element is equal to the number of protons in each such atom. For neutral atoms, it is also equal to the number of electrons.

Sum of number of proton and number of neutron gives the mass number.

protons

the strength of the element

but seriously, it's the number of Protons.
The number of protons +the number of neutrons make up the atomic mass of the element

The atomic number is the number of protons in an atom of an element.

i would add that atomic number reoresents the number of protons in the nucleos equal the atomic mass minus the number of the the number neutrons

Atomic Number, denoted by Z is the number of protons in an atom of the element . Number of electrons equals number of protons in a neutral atom of the element. Mass number, denoted by A, is the number of protons and number of neutrons, which contribute mass to the atom, together, considering the mass of electron as negligible. Thus, number of neutrons = A -- Z. . Atomic weight is not the same as mass number.

The mass number which is the number of protons + the number of neutrons.