Ions (Simplified) - Online Tutor, Practice Problems & Exam Prep

Ions form when elements lose or gain electrons to achieve a stable electron configuration similar to noble gases. Metals typically lose electrons, becoming positively charged cations, while nonmetals gain electrons, forming negatively charged anions. For example, boron loses three electrons to become a cation with a charge of 3+, while oxygen gains two electrons, resulting in a charge of 2-. The term isoelectronic refers to different elements having the same number of electrons, highlighting the significance of electron transfer in ion formation.

Ions (Simplified) Concept 1

Ions are created from losing or gaining electrons by elements in order to become like the noble gases. Now we're going to say that a metal tends to lose electrons to become a positively charged ion called a cation, and nonmetals tend to gain electrons to become a negatively charged ion called an anion. Again, elements do this in order to obtain a stable electron arrangement like the noble gases. So that's the real reason behind them gaining or losing electrons. Now what we need to realize is that associated with this losing and gaining of electrons, we have the term isoelectronic. Isoelectronic just means elements have the same number of electrons. Alright. So just keep in mind when we're forming ions, we're either gaining electrons or losing electrons.

Ions (Simplified) Concept 2

So when thinking of ion formation, let's take a look at boron and oxygen. Alright. So for cation formation, remember, a cation is formed from the losing of electrons. Here we're looking at Boron 11. 11, remember, it represents its mass number or atomic mass. That's the number of protons and neutrons together. 5 just gives us the number of protons within the nucleus. And if the structure is neutral, it also has 5 electrons. We can see the 5 electrons they would have. Now, the 5 electrons are orbiting the nucleus. All of a sudden, though, I decide to remove 3 of those electrons. It now only has 2 electrons remaining. It just lost 3 electrons, so as a result, boron now gets a charge of 3+. Remember, for each electron lost, we become more positive by 1. On the other side, we have our anion formation. Anion means we're gaining electrons. Here we're dealing with oxygen 16. 16 is the mass number again, that's number of protons and neutrons together, so those are found within the nucleus. What we're more concerned with is that its atomic number is 8, which means it has 8 electrons when it's neutral. So here we see 1, 2, 3, 4, 5, 6, 7, and 8. All of a sudden, though, I decide to add 2 additional electrons. So here we've added these 2 additional electrons. So it has its original 8, of course, but then I've added 2 more. When you gain electrons, you gain a negative charge. Because I gained 2 electrons, oxygen's new charge is now 2 minus. So here, this is what we need to think of when we talk about cation and anion formation. Are we losing electrons or are we gaining electrons?

Ions (Simplified) Example 1

So here in this example question, it states, determine the number of protons, neutrons, and electrons for the following cation. Now it's a cation because it possesses a positive charge, that positive charge being 3+. Now, when looking at the other numbers, we know that this 13 here represents our atomic number, which uses the variable z. Remember, the atomic number gives us the number of protons, and because it's 13, that means we have 13 protons. That means that option D cannot be an answer because here we do not have 27 protons. Next, we have the number above the 13 and 27. Remember, that is your mass number, which uses the variable a. Your mass number gives you the number of protons plus neutrons within the element or ion. From this information, we know that the number of neutrons would equal a − z. So it's the mass number minus the atomic number. So that would be 27 minus 13, which would give us 14 neutrons. So, so far, options B and C can be the only correct choices because in A, we do not have 27 neutrons. Now the charge is 3+. 3+ means that you have lost electrons. It means you have lost 3 electrons. When aluminum is neutral, has no charge, it has an equal number of protons and electrons. Okay. But now we've lost 3 electrons, so what does that mean? That means we have 10 electrons remaining. So the answer would have to be C here, and if you want to double check that, you can just say we have 13 protons and 10 electrons, so we know that would be plus 13 plus minus 10, which would give us +3 as an answer. That proves that our charge should be +3 here. So out of all the choices present, only option C gives the correct number for each of the subatomic particles.

Give the correct number of protons, neutrons and electrons for the following isotope:.

• A. 35 protons, 35 neutrons, 81 electrons
• B. 35 protons, 46 neutrons, 36 electrons
• C. 81 protons, 46 neutrons, 82 electrons
• D. 35 protons, 46 neutrons, 34 electrons

In which pair are the two species both isoelectronic and isotopic?

• A.
• B.
• C.
• D.

One isotope of a metallic element has a mass number of 65 and 35 neutrons in the nucleus. The cation that this atom forms has 28 electrons. What is the symbol of the cation?

• A. ⁶⁵Zn
• B. ⁶⁵Ga³⁺
• C. ⁶⁵Zn²⁺
• D. ⁶⁵Ni²⁺

Which of the following is the symbol for the ion with a +4 charge, 30 neutrons and 21 electrons?

• A. ⁵⁵Mn⁴⁺
• B. ⁵¹Cl⁴⁺
• C. ⁵¹Mn⁴⁺
• D. ⁵⁸Ni⁴⁺

Fill in the gaps for the following table.

So here the practice question says, fill in the gaps for the following table. For the first column, we have our symbol, encompassing our element's symbol and its charge. This charge results from adding up all your protons and electrons; thus, we can call it more specifically the net charge. Here, the net charge is 3 plus. Now, protons. We know that protons are equal to our atomic number, Z. But here, we don't have a column for atomic number Z, so we're going to say instead that the protons are connected to the electrons, and together they give us our net charge. Neutrons, we're going to say neutrons here, equal your mass number, which is A, minus Z, which is your atomic number. But, again, because we don't have atomic number as a column, we'll just say since Z equals the number of protons, we're going to say it's minus protons. Then electrons can also be grouped with protons to determine our charge. The mass number here, mass number is A. It comes from looking at the number of protons plus neutrons within an element or an ion. And then charge can be again determined by looking at the number of protons; we know what its atomic number will be. We just look it up on the periodic table. So CO is cobalt. It has 27 protons because its atomic number is 27. Determing the number of neutrons, we're going to take the mass number, which is 59, and minus it by the 27 protons, giving us 32 neutrons. For electrons, the number of protons is 27; how many electrons are here is unknown. Let's see, we don't know how many electrons we have here, so electrons will be unknown. Then we're going to say next that our charge is plus 3 because here's 3 plus. We're going to subtract 27 from both sides. Now, that gives us negative 24, which makes sense because each electron is negatively charged, so that'll give us 24 electrons. So again, we get 24 negative electrons. So you have to go just be 24. For the next one, we know the proton number is 34, so we know the atomic number. Looking on the periodic table, that would give us selenium or Se as our element symbol. The mass number comes from adding up the protons plus the neutrons, so that would give us 80 as our mass number. Then we know the number of protons we have is plus 34, plus our 36 electrons, that's negative 36 because each electron is negatively charged. So overall this would be 2 minus or minus 2, which would be a selenium ion, Se2-. Next, we have 76 here. Look on the periodic table that gives us OS, which is osmium. The number of electrons would be 76, plus the number of electrons, which you don't know, plus the net charge, which is 2 plus or plus 2. Subtract 76 from each side. So that would give us negative 74, which really means we have 74 negatively charged electrons. The mass number here would be 76 protons plus 116 neutrons, so that would give us 192. And then finally, we have here 80 as the number of protons. Look on the periodic table. Oh, actually one more thing, this would be osmium 2+. So we have an atomic number of 84 for the last column or last row, and that gives us Hg, which is called mercury. The mass number would be the number of protons, which is 80, plus number of neutrons, which is 120. So that's 200 for our mass number. And then finally, to determine the overall charge at the end, we have 80 positive protons plus negative 78 for the 78 electrons. So that gives us overall a 2 plus charge. So this would be mercury 2+ ion. This is the approach you need to take in order to find out each one of the subatomic particles, net charge, and mass number for each of the given atoms and ions.

Here’s what students ask on this topic:

What is the difference between a cation and an anion?

A cation is a positively charged ion formed when a metal loses electrons. For example, when boron (B) loses three electrons, it becomes a cation with a charge of 3+ (B³⁺). An anion, on the other hand, is a negatively charged ion formed when a nonmetal gains electrons. For instance, when oxygen (O) gains two electrons, it becomes an anion with a charge of 2- (O^2-). The key difference lies in the type of charge and the process of electron transfer: cations lose electrons, while anions gain electrons.

Why do elements form ions?

Elements form ions to achieve a stable electron configuration similar to that of noble gases. Noble gases have a complete valence shell, which makes them highly stable. Metals tend to lose electrons to form positively charged cations, while nonmetals gain electrons to form negatively charged anions. This electron transfer allows elements to attain a stable, lower-energy state, mimicking the electron configuration of the nearest noble gas.

What does isoelectronic mean in the context of ions?

Isoelectronic refers to different elements or ions that have the same number of electrons. For example, the cation Na⁺ (sodium ion) and the anion F^- (fluoride ion) are isoelectronic because both have 10 electrons. This concept is important in understanding how different ions can have similar electron configurations, despite being different elements or having different charges.

How does boron form a cation?

Boron (B) forms a cation by losing three electrons. In its neutral state, boron has 5 electrons. When it loses 3 electrons, it is left with 2 electrons, resulting in a positively charged ion with a charge of 3+ (B³⁺). This loss of electrons allows boron to achieve a more stable electron configuration.

How does oxygen form an anion?

Oxygen (O) forms an anion by gaining two electrons. In its neutral state, oxygen has 8 electrons. When it gains 2 additional electrons, it has a total of 10 electrons, resulting in a negatively charged ion with a charge of 2- (O^2-). This gain of electrons allows oxygen to achieve a more stable electron configuration.