1.
What is the center of an atom called?
Correct Answer
A. Nucleus
Explanation
The nucleus is the core of an atom and contains most of its mass. It is composed of protons, which are positively charged, and neutrons, which are neutral. This central location of the nucleus plays a crucial role in the atom’s stability and chemical properties. The nucleus determines the identity of an element through the number of protons, which are unique to each element on the periodic table, making it fundamental to understanding atomic structure.
2.
Which particle has a negative charge?
Correct Answer
C. Electron
Explanation
Electrons are subatomic particles with a negative charge and are located in orbitals around the nucleus. They are essential in electricity and chemistry, as their movement between atoms forms electrical currents and chemical bonds. The electron's negative charge balances the positive charge of the protons in the nucleus, which is critical for the overall electrical neutrality of neutral atoms.
3.
What determines the atomic number of an element?
Correct Answer
C. Protons
Explanation
The atomic number of an element is determined by the number of protons in its nucleus. This number not only identifies the element but also directly influences the chemical behavior of the atom. The arrangement of the periodic table is based on atomic numbers, reflecting the orderly increase in proton numbers that define different elements. Understanding atomic numbers is vital for predicting how different elements will interact chemically.
4.
Which is not a subatomic particle?
Correct Answer
A. Molecule
Explanation
Molecules are groups of atoms bonded together and are not considered subatomic particles. In contrast, protons, neutrons, and electrons are individual components that make up atoms. Recognizing the difference between molecules and subatomic particles is important for understanding basic chemical structures and the scale of atomic versus molecular composition.
5.
What is the charge of a neutron?
Correct Answer
C. Neutral
Explanation
Neutrons are neutral particles found in the nucleus of an atom. They do not carry a charge, which distinguishes them from protons and electrons. Neutrons play a critical role in adding mass to an atom and stabilizing the nucleus by offsetting the electrostatic repulsion between protons, which would otherwise push the nucleus apart. Their neutrality helps maintain nuclear stability, especially in larger atoms where proton repulsion is significant.
6.
Which particle is found in the nucleus of an atom?
Correct Answer
B. Proton
Explanation
Protons are positively charged particles located within the nucleus of an atom. Their presence, along with neutrons, constitutes the bulk of an atom’s mass. Protons define the chemical element of an atom, and their number in the nucleus determines the atom's identity and placement in the periodic table. The interaction between protons and neutrons via the strong nuclear force keeps the nucleus stable despite the repulsive force among protons.
7.
What do you call an atom with the same number of protons but more neutrons?
Correct Answer
A. Isotope
Explanation
An isotope of an element has the same number of protons but a different number of neutrons compared to other atoms of that element. This variance in neutron number affects the atom's mass but not its chemical properties, as isotopes behave similarly in chemical reactions. Isotopes are particularly significant in nuclear chemistry and medical applications where their differing stability and radioactive decay patterns are exploited.
8.
What type of bond is formed by the sharing of electrons?
Correct Answer
B. Covalent
Explanation
Covalent bonds are formed when two atoms share one or more pairs of electrons. This type of bonding usually occurs between nonmetal atoms that have similar electronegativities. Sharing electrons allows each atom to attain a more stable electronic configuration, typically mimicking the electron configuration of the nearest noble gas, leading to the formation of stable molecules.
9.
What holds the nucleus together?
Correct Answer
C. Strong force
Explanation
The strong nuclear force, also known simply as the strong force, is responsible for holding the nucleus together. It overcomes the electrostatic repulsion between protons and binds protons and neutrons into a compact nucleus. This force operates over very short ranges and is the most powerful force on the atomic scale, essential for the stability of all atomic nuclei.
10.
Which part of the atom participates in chemical reactions?
Correct Answer
B. Electron
Explanation
Electrons are involved in chemical reactions because they are located in the outermost regions of the atom and can be transferred or shared between atoms. This transfer or sharing of electrons forms chemical bonds, such as ionic or covalent bonds, which determine the chemical properties of compounds. The behavior and arrangement of electrons in atoms dictate how elements will interact and react chemically.