![SOLVED: 'These are the first 20 elements on the periodic table which of these elements had 20 protons in its nucleus (atomic number = 12)? 1. He 2. S 3. Mg 4. SOLVED: 'These are the first 20 elements on the periodic table which of these elements had 20 protons in its nucleus (atomic number = 12)? 1. He 2. S 3. Mg 4.](https://cdn.numerade.com/ask_images/81f8d38ddfeb413a95517912c52a59ca.jpg)
SOLVED: 'These are the first 20 elements on the periodic table which of these elements had 20 protons in its nucleus (atomic number = 12)? 1. He 2. S 3. Mg 4.
![How to learn 1 to 20 elements of periodic table | easy way to learn 1 to 20 elements | class 9 & 10 - YouTube How to learn 1 to 20 elements of periodic table | easy way to learn 1 to 20 elements | class 9 & 10 - YouTube](https://i.ytimg.com/vi/KoINcCyq3X8/maxresdefault.jpg)
How to learn 1 to 20 elements of periodic table | easy way to learn 1 to 20 elements | class 9 & 10 - YouTube
![In the modern periodic table, the positions of 1 to 20 elements are shown here. Identify the elements A and B. Write their atomic number. - Science and Technology 1 | Shaalaa.com In the modern periodic table, the positions of 1 to 20 elements are shown here. Identify the elements A and B. Write their atomic number. - Science and Technology 1 | Shaalaa.com](https://www.shaalaa.com/images/_4:c358c469d03c41f181dbe265c90abeed.png)