Chemistry Practice Review Questions!

Atoms contain neutrons, protons, and electrons. Neutrons are neutral particles found in the nucleus of an atom. Protons are positively charged particles also found in the nucleus. Electrons are negatively charged particles that orbit around the nucleus. These three subatomic particles make up the structure of an atom.

Matter refers to anything that has mass and is made of atoms. This definition encompasses a wide range of substances, including solids, liquids, and gases. It excludes energy and compounds, as these are not considered matter. The presence of electrons alone does not define matter, as there are other particles and subatomic particles present in atoms as well. Therefore, the correct answer is anything that has mass and is made of atoms.

Protons have a positive charge, neutrons have no charge (neutral), and electrons have a negative charge. Therefore, the correct order of charges for the given particles is positive, neutral, negative.

The atomic number of an element tells us the number of protons in the atom. Protons are positively charged particles found in the nucleus of an atom. Each element has a unique number of protons, which determines its identity and place on the periodic table. Therefore, the atomic number provides important information about the element's properties and characteristics.

The atomic number of an atom represents the number of protons in its nucleus. In this case, the number 8 is given as the answer. Therefore, the atomic number of the atom below is 8.

The atomic number of an atom represents the number of protons it contains. Since the atomic number of magnesium is 12, it means that it has 12 protons. The mass number of an atom represents the sum of its protons and neutrons. In this case, the mass number of magnesium is 24. Since the atomic number is 12, it means that there are 12 neutrons in the atom. Lastly, in a neutral atom, the number of electrons is equal to the number of protons. Therefore, magnesium also has 12 electrons.

Atoms are mostly space because they are composed of a nucleus, which contains protons and neutrons, surrounded by electrons that orbit the nucleus. The size of the nucleus is extremely small compared to the overall size of the atom, so most of the atom's volume is empty space. This concept is supported by various scientific experiments and observations.

The mass number of an atom is determined by the sum of its protons and neutrons. Therefore, the correct answer is "neutrons". The other options provided are misspellings of the word "neutrons" but still refer to the same concept.

Isotopes are formed when an atom has the same number of protons but a different number of neutrons. Neutrons are subatomic particles that are found in the nucleus of an atom and have no charge. The number of neutrons in an atom can vary, resulting in different isotopes of the same element.

Bohr changed Rutherford's model of the atom by proposing that electrons could only occupy specific energy levels as they orbit the nucleus. This was a departure from Rutherford's model, which did not specify any restrictions on the placement of electrons. Bohr's model introduced the concept of quantized energy levels, where electrons can only exist in certain discrete orbits around the nucleus. This idea helped explain the stability of atoms and the emission of specific wavelengths of light in atomic spectra.

The valence of an atom refers to the number of bonds that it can form with other atoms. It determines the atom's ability to share or transfer electrons in order to achieve a stable electron configuration. The valence of an atom is determined by the number of electrons in its outermost energy level, also known as the valence shell. By knowing the valence of an atom, we can predict its chemical behavior and the types of compounds it can form.

The mass number of an atom is the sum of the number of protons and neutrons in its nucleus. Since the question provides the number 18 without any context, it can be assumed that it is referring to the mass number of the atom. Therefore, the correct answer is 18.

An anion is a negatively charged atom or molecule that has gained electrons. When an atom or molecule gains one or more electrons, it becomes negatively charged because the number of negatively charged electrons exceeds the number of positively charged protons. Anions are attracted to positively charged particles and are commonly involved in chemical reactions.

The given statement is "Each of these atoms represent a different element." This statement is false because in the diagram, all the atoms have the same number of protons, neutrons, and electrons. Since the number of protons determines the element, if all the atoms have the same number of protons, they would represent the same element, not different elements. Therefore, the correct answer is false.

In the experiment, Earnest Rutherford measured how the particles were deflected when fired at the gold foil. This helped him come up with the "Small Nucleus" model of the atom, as he observed that some particles were deflected at large angles while others passed through with minimal deflection. This led him to conclude that atoms have a small, dense nucleus at the center, which contains most of the atom's mass and positive charge. The deflection of the particles provided evidence for the existence of the nucleus.

John Dalton's idea that atoms in an element are all the same type of atom is still believed to be correct. This concept is a fundamental principle of modern atomic theory, stating that all atoms of a particular element have the same number of protons in their nucleus and therefore the same atomic number. This idea is supported by experimental evidence and is widely accepted in the scientific community.