What is the electron shell rule?
What is the electron shell rule?
Each shell can contain only a fixed number of electrons: The first shell can hold up to two electrons, the second shell can hold up to eight (2 + 6) electrons, the third shell can hold up to 18 (2 + 6 + 10) and so on. The general formula is that the nth shell can in principle hold up to 2(n2) electrons.
Why atomic number is important?
The number of protons in an atom is called its atomic number. This number is very important because it is unique for atoms of a given element. All atoms of an element have the same number of protons, and every element has a different number of protons in its atoms.
What are the first 20 elements and their atomic number?
First 20 Elements
| Atomic Number | Element | Symbol |
|---|---|---|
| 17 | Chlorine | Cl |
| 18 | Argon | Ar |
| 19 | Potassium | K |
| 20 | Calcium | Ca |
Which of the following is true about an element if it has an atomic number of 10?
Answer. Explanation: if its atomic number is 10 then it will be Neon.It is a noble gas.
Which is true for an element?
Which of the following are true for an element? (i) Atomic number = number of protons + number of electrons (ii) Mass number = number of protons + number of neutrons (iii) Atomic mass = number of protons = number of neutrons (iv) Atomic number = number of protons = number of electrons.
Which of the following statement is incorrect about the structure of an atom?
Answer. Atom as a whole in neutral. This point is incorrect.
How can you calculate the number of protons in an atom?
The number of protons in the nucleus of the atom is equal to the atomic number (Z). The number of electrons in a neutral atom is equal to the number of protons. The mass number of the atom (M) is equal to the sum of the number of protons and neutrons in the nucleus.