TEAS version 7 quizlet science

Correct Answer: A

Rationale: The half-life of a radioactive isotope is the time it takes for half of the initial sample to decay. After one half-life, half of the radioactive atoms have decayed. The decay rate, however, refers to the rate at which radioactive atoms decay, which is not directly related to the half-life. Choice B is incorrect because it does not correctly define the half-life. Choice C is incorrect as it refers to the creation of new isotopes, not the decay process. Choice D is incorrect as it describes the energy released during decay, which is not the same as the concept of half-life.

Correct Answer: D

Rationale: The correct answer is Helium (He). Helium has an atomic number of 2, meaning it has 2 protons. It also has 2 neutrons, which gives it a total mass number of 4. Therefore, Helium is an example of an element with an equal number of protons and neutrons. Choice A (Carbon) has 6 protons and usually has more neutrons than protons. Choice B (Oxygen) has 8 protons and 8 neutrons, so the numbers are not equal. Choice C (Lithium) has 3 protons and usually has more neutrons than protons, so it does not fit the criteria of having the same number of protons and neutrons.

Correct Answer: A

Rationale: The periodic table is a tabular arrangement of the chemical elements, organized based on their atomic number, electron configurations, and recurring chemical properties. Elements are placed in rows (periods) and columns (groups) with similar properties. The elements are listed in order of increasing atomic number, which is the number of protons in the nucleus of an atom. This arrangement reveals a periodic repetition of chemical properties, forming the basis of the periodic law. Choice B, which suggests arranging elements based on increasing atomic mass, is incorrect because the periodic table is primarily organized by atomic number, not atomic mass. Choices C and D are also incorrect as the periodic table is not based on reactivity or color of elements, but rather on atomic number and properties.

Correct Answer: C

Rationale: The correct answer is C, the nucleus. The nucleus is the control center of the cell and houses the genetic information in the form of DNA. The Golgi apparatus (choice A) is responsible for packaging and processing proteins, the ribosome (choice B) is involved in protein synthesis, and the endoplasmic reticulum (choice D) is involved in protein and lipid synthesis. Therefore, choices A, B, and D are not the correct answers as they do not house the genetic information or serve as the control center of the cell.

Correct Answer: A

Rationale: Delta waves are slow brain waves associated with deep sleep stages, specifically stages 3 and 4 of non-REM sleep. These waves have a frequency range of 0.5-4 Hz. Choice B (4-8 Hz) refers to theta waves, which are associated with light sleep and relaxation. Choice C (8-13 Hz) corresponds to alpha waves, present during wakeful relaxation. Choice D (13-30 Hz) represents beta waves, seen in active thinking and concentration. Therefore, the correct answer is A because it aligns with the frequency range characteristic of delta waves during deep sleep.