The number of protons can not be changed.
The particle in an atom that cannot change is the number of protons. If that changes, it is no longer the same element.
The nucleus of an atom CANNOT itself contain atoms.
Atoms consist of a nucleus and electrons surrounding the nucleus. You can not change the nucleus by ordinary chemical means but you can remove electrons. However, since the electrons are easily replaced the atom is not considered fundamentally changed by removing electrons, but it is changed. There is a way to change a nucleus that's called "neutron activation" . This involves bombarding the nucleus with slow moving neutrons and letting the nucleus adsorb a neutron. This makes the atom a little heavier and can sometimes make the atom radioactive. Neutron activation is not considered a chemical process but it is a way to change the atom. So I would say it is incorrect to say an atom cannot be changed. Atoms can be changed but its not easy.
A compound can contain a single atom of gold, but a single atom of gold alone, by itself, cannot be a compound.
The proton, otherwise you change the element
The particle in an atom that cannot change is the number of protons. If that changes, it is no longer the same element.
atoms cannot be divided
Electrons can influence an atom's chemical behavior by participating in reactions or forming bonds with other atoms. However, electrons alone cannot change the fundamental identity of an atom, as that is determined by the number of protons in the nucleus.
Sometimes, an atom cannot be split.
I cannot answer this question.
All of the elements of the Periodic Table cannot be broken down into simpler substances.
Atom
An atoms protons cannot change.The number of neutrons can change (gain or lose) to form an isotope (ex. Hydrogen naturally has no neutrons. But it can gain neutrons to form Heavy Hydrogen, or in other words, a Hydrogen Isotope).An atom can gain or lose electrons to form an ion. Usually an atom will gain or lose electrons to fill its valence (outermost) shell. It takes just as much energy to gain an electron as it is to lose one, so an atom will always look to lose or gain the least amount of electrons possible. (ex. Oxygen has 6 valence electrons. It will look to gain 2 electrons, rather than lose 6).Protons: DO NOT CHANGENeutrons: Can change to form an isotopeElectrons: Can change to form an ion
Atom
An atom is the smallest unit of matter that cannot be broken down into smaller particles without losing its unique properties. Each atom consists of a nucleus composed of protons and neutrons, surrounded by electrons in orbitals.
Nuclear change is the change in the nucleus of the atom.
atom