We need a question to answer what number 13
Answer:
Periods
Explanation:
The vertical columns on the periodic table are called groups or families because of their similar chemical behavior. All the members of a family of elements have the same number of valence electrons and similar chemical properties. The horizontal rows on the periodic table are called periods.
The atomic mass can be defined as the mass of neutrons and protons in the atom. The atomic mass of the oxygen isotope is 18 amu.
<h3>What is an atom?</h3>
An atom is the smallest particle comprised of three subatomic units, namely electrons, protons, and neutrons.
The number of electrons in the atoms determines the atomic number, while the number of protons and neutrons determines the atomic mass.
The atomic mass can be given as:
The oxygen isotope has been comprised of 10 neutrons and 8 protons. The atomic mass of the isotope is given as:
The atomic mass of the oxygen isotope is 18 amu. Thus, option C is correct.
Learn more about atomic mass, here:
brainly.com/question/5566317
Gold has a heavy enough nucleus that its electrons must travel at speeds nearing the speed of light to prevent them from falling into the nucleus. This relativistic effect applies to those orbitals that have appreciable density at the nucleus, such as s and p orbitals. These relativistic electrons gain mass and as a consequence, their orbits contract. As these s and (to some degree) p orbits are contracted, the other electrons in d and f orbitals are better screened from the nucleus and their orbitals actually expand.
Since the 6s orbital with one electron is contracted, this electron is more tightly bound to the nucleus and less available for bonding with other atoms. The 4f and 5d orbitals expand, but can't be involved in bond formation since they are completely filled. This is why gold is relatively unreactive.
Hope it helps
Answer:
When you balance a chemical equation you change coefficients.You never change subscripts. A coefficient is a whole number multiplier. To balance a chemical equation you add the coefficients to make sure there are the same number of atoms on each side of the arrow.
Explanation:
Hope this helps. MARK BRAINLEST!!
