1.
What is a negatively charged particle called?
Correct Answer
D. Electron
Explanation
The correct answer is electron. An electron is a negatively charged particle that orbits around the nucleus of an atom. It has a much smaller mass compared to protons and neutrons, and its charge is opposite to that of a proton. Electrons play a crucial role in chemical reactions and the behavior of atoms.
2.
What is contained in the nucleus?
Correct Answer
D. Both Protons and Neutrons
Explanation
The correct answer is "Both protons and neutrons" because the nucleus of an atom contains both protons and neutrons. Protons are positively charged particles found in the nucleus, while electrons are negatively charged particles that orbit around the nucleus. Neutrons, on the other hand, are neutral particles also found in the nucleus. Therefore, the correct answer is that both protons and neutrons are contained in the nucleus.
3.
Which of the following is a neutrally charged particle?
Correct Answer
A. Neutron
Explanation
A neutron is a neutrally charged particle because it has no net electrical charge. It is composed of three quarks - two down quarks and one up quark - which cancel out each other's charges, resulting in a neutral overall charge. Unlike protons, which have a positive charge, and electrons, which have a negative charge, neutrons do not attract or repel other charged particles. Therefore, they are considered to be neutrally charged.
4.
What is the atomic number?
Correct Answer
C. The number of positive charges (protons) in the nucleus of an atom of a given element
Explanation
The atomic number of an element represents the number of protons in the nucleus of an atom of that element. Protons are positively charged particles, and their number determines the identity of the element. Therefore, the correct answer is "The number of positive charges (protons) in the nucleus of an atom of a given element."
5.
There are _______________electrons in the third orbit.
Correct Answer
eighteen, 18
Explanation
The third orbit of an atom can hold a maximum of eighteen electrons. This is because the first orbit can hold up to two electrons, the second orbit can hold up to eight electrons, and the third orbit can also hold up to eighteen electrons. In general, the formula for determining the maximum number of electrons in an energy level or orbit is given by 2n^2, where n represents the principal quantum number of the orbit. For the third orbit, the maximum number of electrons would be 18.
6.
On the periodic table elements are arranged by their____________________________.
Correct Answer
Atomic number
Explanation
Elements on the periodic table are arranged by their atomic number. The atomic number represents the number of protons in an atom's nucleus, which determines the element's identity. This arrangement allows elements to be organized in order of increasing atomic number, from left to right and top to bottom. The periodic table's structure reflects trends in properties such as atomic size, electronegativity, and reactivity, making it a useful tool for understanding and predicting the behavior of elements.
7.
Electrons, protons, and neutrons are all in an_________.
Correct Answer
atom
Explanation
Electrons, protons, and neutrons are all found in an atom. An atom is the basic unit of matter, consisting of a nucleus (which contains protons and neutrons) and electron shells (which contain electrons). These subatomic particles are essential components of an atom and are responsible for its properties and behavior. Therefore, the correct answer is atom.
8.
Who discovered the electron?
Correct Answer
D. J.J. Thomson
Explanation
J.J. Thomson is the correct answer because he is credited with discovering the electron. In 1897, Thomson conducted experiments using cathode rays and concluded that they were made up of negatively charged particles, which he called electrons. This discovery revolutionized our understanding of atomic structure and laid the foundation for modern physics.