Home › NY Regents Earth and Space Sciences › Science › Radiation and Spectra › What decides which element an atom belongs to?
What decides which element an atom belongs to?
AIts number of neutrons
BIts number of protons
CIts number of isotopes
DIts number of orbits
Answer & Solution
Correct answer: B. Its number of protons
1. An atom's nucleus holds protons and, in most cases, neutrons as well.
2. The count of protons fixes the identity of the element.
3. Six protons make carbon, eight make oxygen and twenty six make iron.
4. Changing the neutron count only gives a different isotope of the same element.
_Source: OpenStax Astronomy (CC BY 4.0), Ch 4 "Earth, Moon, and Sky" and Ch 5 "Radiation and Spectra", section 5.4 The Structure of the Atom_
Related questions
Excited atoms give back the very light they absorbed, yet dark absorption lines still survDark lines cross the spectrum of the Sun. Where do the atoms that remove those colors sit?An oxygen atom can be ionized up to eight times while a hydrogen atom can be ionized only A hydrogen line normally at 500 nanometers is measured at 500.1 nanometers in a star's speTwo stars are the same size and the same distance away, but star B is three times as hot aWien's law uses a constant of 3 million nanometer kelvins. A star radiates most strongly aA star is moved to ten times its present distance from us. How much fainter does it look?What name is given to a single self-contained packet of electromagnetic energy?