Identify Indium Isotopes: A Periodic Table Guide

Hey chemistry whizzes! Ever stared at the periodic table and wondered how you can use it to figure out if something is an isotope of a specific element, like our buddy Indium (In)? Well, buckle up, because we're about to dive deep into this and uncover which of the given options could actually be an isotope of indium. It's not as complicated as it sounds, guys, and once you get the hang of it, you'll be spotting isotopes like a pro!

Understanding Isotopes: The Core Concept

So, what exactly is an isotope, anyway? Think of it like this: every element on the periodic table has a unique identity, right? That identity is primarily determined by the number of protons in its atom's nucleus. This number is called the atomic number (Z). For indium, its atomic number is 49. This means every single atom of indium, no matter what, must have 49 protons. If it doesn't have 49 protons, it's not indium, simple as that.

Now, where do isotopes come into play? Isotopes are basically different versions of the same element. They have the same number of protons (so they're still the same element), but they have a different number of neutrons in their nucleus. Neutrons are the other subatomic particles hanging out in the nucleus, and they don't affect the element's identity. However, adding or removing neutrons does change the atom's mass number (A). The mass number is simply the total count of protons and neutrons in the nucleus ($A = Z + N$, where N is the number of neutrons). So, while all indium atoms have 49 protons, some might have more neutrons than others, leading to different mass numbers. These different versions with varying neutron counts are what we call isotopes.

It's super important to remember this distinction: Z defines the element, while N (and therefore A) can vary for isotopes of that element. This is the golden rule we'll use to crack this problem. We need to find options where the number of protons (Z) is 49, and the number of neutrons (N) can be anything, as long as it results in a valid mass number (A). The periodic table is your best friend here because it explicitly tells you the atomic number (Z) for every element. For indium, we are laser-focused on finding that Z=49.

Cracking the Code: Analyzing the Options

Alright, let's put our detective hats on and examine each option, keeping our core concept in mind: for indium, Z must be 49. We'll also check if the given numbers make sense in terms of the relationship $A = Z + N$.

Option A: $N=61, A=113$

In this option, we are given the number of neutrons ($N=61$) and the mass number ($A=113$). To be an isotope of indium, we first need to determine its atomic number (Z). Using the formula $A = Z + N$, we can rearrange it to find Z: $Z = A - N$. Plugging in the values, we get $Z = 113 - 61 = 52$. Since the atomic number is 52, this atom is not indium. In fact, element number 52 is Tellurium (Te). So, option A is a no-go for indium isotopes.

Option B: $Z=49, A=113$

Now, let's look at option B. Here, we are given $Z=49$ and $A=113$. The first and most crucial check is the atomic number. Is $Z=49$ the atomic number for indium? Yes, it is! This is a fantastic start. Now, let's see if the mass number makes sense. If $Z=49$ and $A=113$, we can calculate the number of neutrons: $N = A - Z = 113 - 49 = 64$. Since we have a valid atomic number for indium ($Z=49$) and a plausible number of neutrons ($N=64$) that results in a valid mass number ($A=113$), this option could indeed be an isotope of indium. Keep this one in the 'yes' pile!

Option C: $A=110, N=49$

Moving on to option C, we have $A=110$ and $N=49$. Let's find the atomic number (Z) using $Z = A - N$. So, $Z = 110 - 49 = 61$. An atomic number of 61 corresponds to the element Promethium (Pm), not Indium. Even though the number 49 appears here, it's given as the number of neutrons, not protons. Remember, it's the number of protons (Z) that defines the element. Therefore, option C is not an isotope of indium.

Option D: $N=64, Z=49$

Finally, let's examine option D. We are given $N=64$ and $Z=49$. The atomic number $Z=49$ immediately tells us this element is Indium. Now, let's check the mass number. Using $A = Z + N$, we get $A = 49 + 64 = 113$. So, this represents an atom of Indium with 49 protons and 64 neutrons, giving it a mass number of 113. This is the exact same isotope we identified in option B! It's just presented with the numbers in a different order. Therefore, option D is also a valid isotope of indium.

The Verdict: Two Correct Answers!

So, after our detailed breakdown, we've found two options that fit the bill for being an isotope of indium. Remember, the key is always to look for the atomic number (Z) that matches the element in question. For indium, that number is 49.

• Option B ($Z=49, A=113$) is correct because it explicitly states $Z=49$, confirming it's Indium, and the mass number $A=113$ is valid.
• Option D ($N=64, Z=49$) is correct because it also explicitly states $Z=49$, confirming it's Indium, and the number of neutrons $N=64$ leads to a valid mass number $A=113$ ($49+64=113$).

Options A and C were ruled out because their calculated atomic numbers were not 49. It's all about that atomic number, folks!

Why This Matters: The Significance of Isotopes

Understanding isotopes isn't just for acing chemistry tests, although it's definitely great for that! Isotopes have a massive impact on various scientific fields. For instance, Indium-113 (which is what options B and D represent) is a stable isotope. Indium also has radioactive isotopes, like Indium-111, which is used in medical imaging. Different isotopes of an element can have vastly different properties, especially their stability (whether they are radioactive or not). This is due to the different number of neutrons affecting the stability of the nucleus.

In nuclear physics, isotopes are fundamental. They are used in carbon dating (using Carbon-14), in nuclear power plants (Uranium-235), and in cancer treatments (Cobalt-60). Even in everyday life, some medical diagnostic tools rely on specific radioactive isotopes. So, the next time you see a periodic table, remember it's not just a list of elements; it's a gateway to understanding the diverse world of atoms and their isotopes, each with its own unique story and applications. Keep exploring, keep learning, and never underestimate the power of those protons and neutrons!