# Atomic Number Questions and Answers (Q&A) #### megabunny

It's 2 as first it's hydrogen then helium then no. 3 is lithenium #### esthomas

On the periodic table, each element is assigned an atomic number. Besides showing its placement on the periodic table, the atomic number shows the number of protons located in the center of the atom. In this case since the element has 5 protons in it, then its atomic number is five. Using this information, you can also find out other information about the element.

Since you have the number of neutrons in this element which is 5 and the atomic number, you can add those numbers together to find the mass number of the element. Dmitri Mendeleev is known for creating the periodic table. He organized the elements based on the weight of each atom. Over time more elements were added to the table as they were discovered. #### awilliams

The answer to this is letter A. There is sometimes a need for electrons and protons to be equal when the given atom is neutral in charge. An atom has three atomic particles. The first one is the proton which has a positive charge. The second one is the electron which has a negative charge, and lastly, there is the neutron which does not have any charge.

For this particular question, A is the right answer because of the given atomic number. The atomic number is 12 which means that it is the sum of both the protons and the electrons that are present. If the other choices would be added, the atomic number would be too much. It is only A that will give the sum of 12. #### awilliams

3,4,3. Protons, neutrons, and electrons are the three basic parts of an atom. The electron is a negatively charged molecule that is located at the center of the atom in the nucleus. The neutron does not have any charge.

The number of neutrons affects the mass and radioactivity of the atom. The easiest way to find the number on the periodic table. That number is the number of protons. The easiest way to find the number is equal to the number of protons, neutrons, and electrons.

Identify the net charge. Subtract the charge from the atomic number. Add the charge to the atomic number. Add the charge to the atomic integer for negative ions. This is how to find the number of protons, neutrons, and electrons. Protons and neutrons make up the nucleus. #### rachit gupta

Atomic number of helium is 2 #### Coulter

The correct answer is option A
If Phosphorous has an atomic mass of 30 and 15 neutrons the proton number is most likely 15.

The mass number of of atoms in an element is equal to the sum total of the number of neutrons and protons. Since we have the atomic mass and the number of neutrons, it is easy to determine the number of protons
Atomic mass = number of proton + number of neutrons
Let X be number of protons
30 = X + 15
X = 30 – 15
= 15
Therefore the number of proton is 15.  