Každý atóm má svoje "rodné číslo" - protónové a nukleónové... Show more
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Angličtina
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Updated Mar 13, 2026
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Čo je protónové a nukleónové číslo?
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Základy atómov a kľúčové pojmy
Atómy sú ako malé planétky - v strede majú jadro s protónmi a neutrónmi, okolo ktorého lietajú elektróny. Protóny majú kladný náboj (+1), elektróny záporný (-1) a neutróny sú neutrálne.
Protónové číslo (Z) je ako identifikačné číslo prvku. Hovorí ti, koľko protónov má atóm v jadre. Ak má atóm 6 protónov, je to vždy uhlík, ak má 8 protónov, je to vždy kyslík.
V neutrálnom atóme sa počet protónov vždy rovná počtu elektrónov. Prečo? Lebo kladné a záporné náboje sa navzájom vyrušia. Protónové číslo nájdeš v periodickej tabuľke ako menšie celé číslo nad symbolom prvku.
Tip: Protónové číslo sa nikdy nemení pre ten istý prvok - je to jeho jedinečná "totožnosť"!
Nukleónové číslo a výpočty
Nukleónové číslo (A) ti povie, aká je približná hmotnosť atómu. Je to súčet protónov a neutrónov v jadre, lebo elektróny sú tak ľahké, že sa počítajú.
Vzorec je jednoduchý: A = Z + počet neutrónov. Ak chceš zistiť počet neutrónov, stačí ti: počet neutrónov = A - Z.
Atóm sa zapisuje ako ᴬzX, kde X je symbol prvku, A je nukleónové číslo (hore) a Z je protónové číslo (dole). Napríklad ¹²₆C znamená uhlík s 6 protónmi a 6 neutrónmi.
Pamätaj: Nukleónové číslo je vždy väčšie alebo rovné protónovému číslu!
Izotopy - rovnaký prvok, iná hmotnosť
Izotopy sú atómy toho istého prvku, ktoré majú rovnaký počet protónov, ale rôzny počet neutrónov. Majú teda rovnaké Z, ale rôzne A.
Dobrý príklad je vodík: bežný vodík ¹₁H má 1 protón a 0 neutrónov, deutérium ²₁H má 1 protón a 1 neutrón, trícium ³₁H má 1 protón a 2 neutróny. Všetky tri sú stále vodík!
Izotopy sa správajú chemicky rovnako, lebo majú rovnaký počet protónov a elektrónov. Líšia sa len hmotnosťou kvôli rôznemu počtu neutrónov.
Kľúč k úspechu: Izotopy = rovnaké protóny, rôzne neutróny!
Praktické príklady na precvičenie
Pre kyslík ¹⁶₈O: Z = 8, A = 16, má 8 protónov, 8 elektrónov (neutrálny atóm) a 8 neutrónov (16-8=8).
Pre sodík ²³₁₁Na: Z = 11, A = 23, má 11 protónov, 11 elektrónov a 12 neutrónov (23-11=12).
Keď máš ³⁵₁₇Cl a ³⁷₁₇Cl, sú to izotopy chlóru. Oba majú 17 protónov, ale prvý má 18 neutrónov a druhý 20 neutrónov.
Pre test si zapamätaj: Z = počet protónov = počet elektrónov (pre neutrálny atóm), A = protóny + neutróny!
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very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
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I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
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iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
Čo je protónové a nukleónové číslo?
Každý atóm má svoje "rodné číslo" - protónové a nukleónové číslo. Tieto čísla ti povedia všetko potrebné o tom, z čoho sa atóm skladá a aký je to prvok. Bez nich by sme sa v chémii vôbec nevedeli orientovať!
Základy atómov a kľúčové pojmy
Atómy sú ako malé planétky - v strede majú jadro s protónmi a neutrónmi, okolo ktorého lietajú elektróny. Protóny majú kladný náboj (+1), elektróny záporný (-1) a neutróny sú neutrálne.
Protónové číslo (Z) je ako identifikačné číslo prvku. Hovorí ti, koľko protónov má atóm v jadre. Ak má atóm 6 protónov, je to vždy uhlík, ak má 8 protónov, je to vždy kyslík.
V neutrálnom atóme sa počet protónov vždy rovná počtu elektrónov. Prečo? Lebo kladné a záporné náboje sa navzájom vyrušia. Protónové číslo nájdeš v periodickej tabuľke ako menšie celé číslo nad symbolom prvku.
Tip: Protónové číslo sa nikdy nemení pre ten istý prvok - je to jeho jedinečná "totožnosť"!
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Nukleónové číslo a výpočty
Nukleónové číslo (A) ti povie, aká je približná hmotnosť atómu. Je to súčet protónov a neutrónov v jadre, lebo elektróny sú tak ľahké, že sa počítajú.
Vzorec je jednoduchý: A = Z + počet neutrónov. Ak chceš zistiť počet neutrónov, stačí ti: počet neutrónov = A - Z.
Atóm sa zapisuje ako ᴬzX, kde X je symbol prvku, A je nukleónové číslo (hore) a Z je protónové číslo (dole). Napríklad ¹²₆C znamená uhlík s 6 protónmi a 6 neutrónmi.
Pamätaj: Nukleónové číslo je vždy väčšie alebo rovné protónovému číslu!
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Izotopy - rovnaký prvok, iná hmotnosť
Izotopy sú atómy toho istého prvku, ktoré majú rovnaký počet protónov, ale rôzny počet neutrónov. Majú teda rovnaké Z, ale rôzne A.
Dobrý príklad je vodík: bežný vodík ¹₁H má 1 protón a 0 neutrónov, deutérium ²₁H má 1 protón a 1 neutrón, trícium ³₁H má 1 protón a 2 neutróny. Všetky tri sú stále vodík!
Izotopy sa správajú chemicky rovnako, lebo majú rovnaký počet protónov a elektrónov. Líšia sa len hmotnosťou kvôli rôznemu počtu neutrónov.
Kľúč k úspechu: Izotopy = rovnaké protóny, rôzne neutróny!
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Praktické príklady na precvičenie
Pre kyslík ¹⁶₈O: Z = 8, A = 16, má 8 protónov, 8 elektrónov (neutrálny atóm) a 8 neutrónov (16-8=8).
Pre sodík ²³₁₁Na: Z = 11, A = 23, má 11 protónov, 11 elektrónov a 12 neutrónov (23-11=12).
Keď máš ³⁵₁₇Cl a ³⁷₁₇Cl, sú to izotopy chlóru. Oba majú 17 protónov, ale prvý má 18 neutrónov a druhý 20 neutrónov.
Pre test si zapamätaj: Z = počet protónov = počet elektrónov (pre neutrálny atóm), A = protóny + neutróny!
Sign up to see the contentIt's free!
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Sign up to see the contentIt's free!
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Sign up to see the contentIt's free!
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Improve your grades
Join milions of students
We thought you’d never ask...
What is the Knowunity AI companion?
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
Where can I download the Knowunity app?
You can download the app from Google Play Store and Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
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The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE Knowunity AI. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user