Determine the number of protons and the number of neutrons in each isotope. a. 40 19 K b. 226 88 Ra c. 99 43 Tc d. 33 15 P

Welcome back. Everyone were asked how many neutrons and protons are in the phosphorus, isotope phosphorus? 35. Let's take a closer look at the symbol we have the number 35 in the left hand exponents, which we should recognize as our mass number or atomic mass. And recall that this number is calculated as the sum of the number of protons and number of neutrons in our atom. But let's recall that protons are actually represented by the symbol Z. Next, we notice the number 15 left hand subscript recall that this number represents our atomic number and is calculated from taking We're from looking at the periodic table and seeing that in group five, a phosphorus has the number 15 over it. And recall that our atomic number is represented also as a symbol Z. And so we can say that our number of protons slash symbol Z is equal to also 15. Now, a note that we want to make is that in neutral atoms only. So in Adam without a charge, our number of protons are equal to the number of electrons. And in this case, we have an isotope of phosphorus which is uncharged there's no charge in our symbol. And so we can say we also have 15 electrons, right. So, so far, we've determined one answer being that we have 15 protons. We need our number of neutrons still though. So because we know that our mass number is the sum of protons plus neutrons, we can write out an equation saying that 35 is equal to 15 plus our number of neutrons. And so two sulfur N we would take minus 15. That's right, that meter -15 from both sides. And so we can say that N is equal to a value of 20. And so we have 20 neutrons in our atom of phosphorus. 35. So what's highlighted in yellow are our two final answers corresponding to choice a in the multiple choice? Thanks for watching and I'll see everyone in the next video.

Ch.2 - Atoms & Elements

Tro - Chemistry: A Molecular Approach 4th Edition

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Ch.2 - Atoms & Elements

Problem 54

Chapter 2, Problem 54

Determine the number of protons and the number of neutrons in each isotope. a. ⁴⁰₁₉K b. ²²⁶₈₈Ra c. ⁹⁹₄₃Tc d. ³³₁₅P

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Identify the atomic number (Z) and the mass number (A) for each isotope. The atomic number is the subscript and represents the number of protons. The mass number is the superscript and represents the total number of protons and neutrons.

For each isotope, the number of protons is equal to the atomic number (Z).

To find the number of neutrons in each isotope, subtract the atomic number (Z) from the mass number (A). The formula to use is: Number of neutrons = A - Z.

Apply the formula to each isotope: a. For 40 19K, subtract 19 from 40. b. For 226 88Ra, subtract 88 from 226. c. For 99 43Tc, subtract 43 from 99. d. For 33 15P, subtract 15 from 33.

Summarize the results for each isotope, listing the number of protons and the number of neutrons calculated.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Isotopes

Isotopes are variants of a particular chemical element that have the same number of protons but different numbers of neutrons. This means they share the same atomic number but have different mass numbers. For example, potassium-40 (40 19K) has 19 protons and 21 neutrons, while potassium-39 would have 19 protons and 20 neutrons.

Atomic Number and Mass Number

The atomic number of an element, represented by the lower number in isotope notation, indicates the number of protons in the nucleus. The mass number, shown as the upper number, is the total count of protons and neutrons. For instance, in 40 19K, the atomic number is 19 (protons), and the mass number is 40, leading to the calculation of neutrons as 40 - 19 = 21.

Nuclear Composition

The nuclear composition of an atom refers to the arrangement and quantity of protons and neutrons within its nucleus. Understanding this composition is essential for identifying isotopes and their properties. For example, knowing that 226 88Ra has 88 protons allows us to determine it has 138 neutrons (226 - 88 = 138), which is crucial for understanding its stability and behavior in nuclear reactions.