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The atomic number of an element is determined by the number of:
electrons
protons
neutrons
both protons and neutrons
protons
The atomic number of an element is defined by the number of protons present in the nucleus of its atom. This value uniquely identifies a chemical element and determines its identity in the periodic table.
The atomic number of an element is defined by the number of protons present in the nucleus of its atom. This value uniquely identifies a chemical element and determines its identity in the periodic table.
Think of the atomic number as a unique 'ID number' or 'Aadhaar number' for an element; just as a person is identified by their unique ID, an element is identified by its unique count of protons in the nucleus.
Z=P
Where Z is the atomic number and P is the number of protons in the nucleus.
Every atom consists of a nucleus containing positively charged protons and neutral neutrons, surrounded by negatively charged electrons. The number of protons, known as the proton number (Z), is constant for all atoms of a specific element, regardless of the number of neutrons (isotopes) or electrons (ions). In a neutral atom, the number of electrons equals the number of protons, but the protons remain the fundamental defining characteristic for the atomic identity.
Atomic number is denoted by the symbol Z.
It is strictly equal to the count of protons in the nucleus.
Changing the number of protons creates a completely different element (nuclear transmutation).
Changing the number of neutrons creates an isotope of the same element.
Changing the number of electrons creates an ion of the same element.
Used to organize elements in the Periodic Table.
Used in nuclear physics to identify atomic species.
The sum of protons and neutrons is called the Mass Number (A), calculated as A=P+N.
Option A is incorrect because electron counts vary in ions. Option C is incorrect because neutron counts vary in isotopes. Option D is incorrect as the mass number involves both particles.
B is correct тАФ The atomic number of an element is defined strictly by the number of protons in its nucleus.
Always remember that while electrons determine chemical bonding behavior, the protons are the 'DNA' of the atom that decides which element it is.
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