An element in the periodic table has 19 protons and 20 neutrons. The number of electrons in this element is 19. The atomic number is 19 and the mass number is 39.
The Correct Answer and Explanation is:
ChatGPT said:
Correct Answer:
K, 19, 19, 39
Explanation:
To determine the correct element and complete the missing information, we analyze the given data step-by-step.
1. Protons = 19
The number of protons determines the atomic number of an element. An element with 19 protons has an atomic number of 19. Looking at the periodic table, potassium (K) is the element with atomic number 19.
2. Neutrons = 20
The mass number of an element is the sum of the protons and neutrons:Mass number=Protons+Neutrons=19+20=39\text{Mass number} = \text{Protons} + \text{Neutrons} = 19 + 20 = 39Mass number=Protons+Neutrons=19+20=39
3. Electrons = 19
In a neutral atom, the number of electrons is equal to the number of protons, so this element also has 19 electrons.
4. Summarizing:
- Element: Potassium (symbol K)
- Number of electrons: 19
- Atomic number: 19
- Mass number: 39
This matches the multiple-choice option:
K, 19, 19, 39
Conclusion:
The periodic table is organized by atomic number, which corresponds to the number of protons in an element. Each element has a unique number of protons. Potassium (K) has 19 protons and, in its neutral state, 19 electrons. When you are given the number of neutrons, you can determine the mass number by adding the protons and neutrons together. This is important in distinguishing isotopes of the same element, which have the same number of protons but different numbers of neutrons. In this case, potassium with 20 neutrons is the isotope K-39, which is the most common and stable isotope of potassium.
