57.0 is it rounded to three sig figs. You count three spaces then round from there, which would be the zero and you would round down because the four is there.
Answer:
Protons: 2.
Electrons: 2.
Neutrons: 2.
Explanation:
Hello,
In this case, since an atom's atomic number is equal to the number of electrons, considering the electron configurations, taking into account that helium-4 is neither positively nor negatively charged, we can infer that the number of electrons equal the number of protons, which in this case are 2, due to the fact that is atomic number is 2.
Moreover, as helium-4's atomic number is 4 as a whole number, we compute the number of neutrons by using the shown below equation:

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Answer: 1 mol of oxygen, O₂, and 1 mol of CO will have the same number of molecules, and the same number of atoms.
Justification:
Althought the question is too open, other answers may arise, the most remarkable similarity between the two compounds is that both are diatomic.
That means that both molecules oxygen, O₂, and carbon monoxide, CO have two atoms.
So, 1 mol of oxygen, O₂, and 1 mol of CO will have the same number of molecules, and the same number of atoms.
You must remember that 1 mol means a specific number. It is Avogadro's number, which is 6.022 × 10 ²³.
So 1 mol of CO and 1 mol of O₂ are the same number of representative particles: 6.022 ×10²³ molecules eac, and two times that number of atoms each (since each molecule has two atoms).
Carbon 12 and carbon 14 are two isotopes of the elements carbon.the difference between carbon 12 and carbon 14 is the number r of neutrons in each atom.the number given after the atom name (carbon) indicates the numbers of protons plus neutron is an atom or iron. Atom of both isotopes of carbon contain 6 protons