Biology Test 2 Part 1

The correct answer is "lectons" which is not a component of an atom. This is likely a typographical error as the correct term is "electrons". Electrons are negatively charged particles that orbit around the nucleus of an atom. Protons and neutrons are the other two components of an atom, with protons carrying a positive charge and neutrons carrying no charge.

Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons. This means that the only difference between isotopes of the same element is the number of neutrons they have. Therefore, the statement is true.

The octet rule is a stability rule in chemistry that states that the outer electron shell of an atom is most stable when it contains eight electrons. This is because having a full outer shell allows the atom to achieve a stable electron configuration similar to that of noble gases. This stability is important in determining the chemical behavior of atoms, as atoms will often gain, lose, or share electrons in order to achieve a full outer shell and become more stable.

Covalent bonds result from the sharing of electrons between atoms. In a covalent bond, two or more atoms share electrons in order to achieve a stable electron configuration. This type of bond is typically formed between nonmetal atoms. The shared electrons are attracted to the positively charged nuclei of both atoms, creating a strong bond. Covalent bonds are important in many biological and chemical processes, as they allow atoms to form stable molecules by completing their outer electron shells.

The periodic table provides information about the various elements, including their atomic number, atomic mass, and chemical symbol. It also indicates the number of protons in an element, which determines its identity, and the number of valence electrons, which determines its chemical reactivity. Additionally, the periodic table can be used to predict whether an element is more likely to form ionic or covalent bonds based on its position and properties. Therefore, the correct answer is that the periodic table indicates whether an element forms ionic or covalent bonds.

When an atom gains electrons, it becomes negatively charged because the number of electrons exceeds the number of protons. This creates an imbalance in the atom's charge, resulting in a negatively charged ion.

Nitrogen requires 3 electrons to fill its outer shell. The outer shell of nitrogen has a total of 5 electrons, but it needs 8 electrons to have a full outer shell. Therefore, it requires 3 more electrons to complete its outer shell.

The atomic number of an atom refers to the number of protons in its nucleus. It is also equal to the number of electrons in a neutral atom. This is because in a neutral atom, the number of protons (positively charged particles) is equal to the number of electrons (negatively charged particles), resulting in a balanced charge. Therefore, the correct answer is that the atomic number tells you the number of protons in the atom, as well as the number of its electrons if the atom has a neutral charge.

A polar covalent bond is formed when two atoms with different electronegativities come together to share electrons. In this type of bond, the electrons are not shared equally between the atoms, resulting in a partial positive charge on one atom and a partial negative charge on the other. This unequal sharing of electrons is due to the difference in electronegativity, which causes the more electronegative atom to attract the shared electrons more strongly. Therefore, in a polar covalent bond, the electrons are always shared unequally.

The correct answer is "atoms basic to life." This means that CHNOPS are essential atoms that are necessary for the existence and functioning of living organisms. These atoms are found in all living things and are fundamental to the structure and function of biological molecules such as proteins, carbohydrates, nucleic acids, and lipids. Therefore, CHNOPS are considered the building blocks of life.

Electrons at various energy levels contribute almost no weight to an atom. While protons and neutrons have relatively large masses, electrons are much lighter. They orbit around the nucleus in energy levels, and their individual masses are negligible compared to protons and neutrons. Therefore, the weight of an atom is primarily determined by the protons and neutrons in the nucleus, while the electrons contribute very little to the overall weight.

An atom that has two electrons in the outer shell, such as calcium, would most likely lose these two electrons and become a positively charged ion. This is because atoms tend to gain or lose electrons in order to achieve a stable electron configuration, usually by acquiring a completed outer shell. In the case of calcium, losing two electrons would result in a stable electron configuration similar to that of a noble gas, which is energetically favorable.

In the molecule CH4, all atoms are sharing electrons. This is because carbon has four valence electrons and needs four more electrons to complete its octet. Each hydrogen atom contributes one electron to form a covalent bond with carbon, resulting in a total of four shared electrons. This sharing of electrons allows each atom to achieve a stable electron configuration.

Ionic bonds are formed when one atom donates electrons to another atom, resulting in the formation of positively and negatively charged ions. In biological systems, where water is abundant, the polar nature of water molecules allows them to surround and interact with the charged ions. The water molecules form hydration shells around the ions, weakening the ionic bonds and causing the molecules held together by these bonds to dissociate. Therefore, molecules held together by ionic bonds tend to dissociate in biological systems due to the water content.