Answer:
Explanation:
The first ionization energy varies in a predictable way across the periodic table. The ionization energy decreases from top to bottom in groups, and increases from left to right across a period. Thus, helium has the largest first ionization energy, while francium has one of the lowest.
Answer:
Density is a measurement that compares the amount of matter an object has to its volume. An object with much matter in a certain volume has high density.
Explanation:
Diagram of the nuclear composition, electron configuration, chemical data, and valence orbitals of an atom of neodymium-144 (atomic number: 60), an isotope of this element. The nucleus consists of 60 protons (red) and 84 neutrons (orange). 60 electrons (white) successively occupy available electron shells (rings).
Answer:
However, various hydrogen isotopes, such as H-2, have one proton and one neutron; H-3 has one proton and two neutrons, etc. The sum of the protons and neutrons in an atom's nucleus is its atomic mass. Thus, the atomic mass of the H-2 isotope is two, the atomic mass of the H-3 isotope is three, and so forth.
Explanation:
