1. The right answer is electron.
The electron, one of the components of the atom with neutrons and protons, is an elementary particle that has an elementary charge of negative sign. It is fundamental in chemistry because it participates in almost all types of chemical reactions and is an essential element of the bonds present in molecules.
The mass of an electron is 9.109 × 10-31 kg. The electron is about 2000 times lighter than the proton and neutron in the nucleus. The masses of the proton and the neutron are almost identical (10-27 kg).
2. The right answer is rapidly moving electrons.
The chemical, physical and electrical properties of an atom are related to the number of protons in the nucleus, which determines the number of electrons in the electron cloud.
The electron cloud is formed of electrons rotating at high speed around the nucleus in very complex trajectories. The electronic cloud is composed of electrons so its electric charge is always negative.
3. The right answer is Atoms of the same element can have different numbers of neutrons.
Isotopes (of a certain chemical element) are called the nuclides sharing the same number of protons (characteristic of this element), but having a different number of neutrons.
So what characterizes an element is the number of protons.
By extension, isotope is often called a nuclide characterized by its number of protons Z and its number of neutrons N (or its mass number A = Z + N), but without distinction regarding its spin or energy state.
4. The right answer is 8.
The atomic number (Z) is the term used in chemistry and physics to represent the number of protons in an atom. An atom can be schematized as a first approach by a compact agglomeration (atomic nucleus) of protons (p +) and neutrons (n), around which circulate electrons (e-).
5. The right answer is 18.
The relative atomic mass (or atomic weight) is the mass of an atom in particular or a chemical element in general (in which case an isotopic mixture is envisaged) expressed as a multiple of a reference elementary mass that wants to be close to that of a single nucleon. Indeed the mass of an atom is proportional in first approximation to the number of its nucleons (protons and neutrons), said number of mass.
