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Question
What are the atomic numbers of elements whose outermost electrons is represented by 3p5?
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Solution
3p5
Completing the electron configuration of the element as
1s2 2s2 2p6 3s2 3p5
∴ Number of electrons present in the atom of the element = 2 + 2 + 6 + 2 + 5 = 17
∴ Atomic number of the element = 17
RELATED QUESTIONS
With the help of given Table, find out the mass number of sulphur atom.
| Composition of Atoms of the First Eighteen Elements with Electron Distribution in Various Shells | ||||||||||
| Name of Element | Symbol | Atomic Number | Number of protons | Number of Neutrons | Number of Electrons | Distribution of Electrons | Valency | |||
| K | L | M | N | |||||||
| Hydrogen | H | 1 | 1 | - | 1 | 1 | - | - | - | 1 |
| Helium | He | 2 | 2 | 2 | 2 | 2 | - | - | - | 0 |
| Lithium | Li | 3 | 3 | 4 | 3 | 2 | 1 | - | - | 1 |
| Beryllium | Be | 4 | 4 | 5 | 4 | 2 | 2 | - | - | 2 |
| Boron | B | 5 | 5 | 6 | 5 | 2 | 3 | - | - | 3 |
| Carbon | C | 6 | 6 | 6 | 6 | 2 | 4 | - | - | 4 |
| Nitrogen | N | 7 | 7 | 7 | 7 | 2 | 5 | - | - | 3 |
| Oxygen | O | 8 | 8 | 8 | 8 | 2 | 6 | - | - | 2 |
| Fluorine | F | 9 | 9 | 10 | 9 | 2 | 7 | - | - | 1 |
| Neon | Ne | 10 | 10 | 10 | 10 | 2 | 8 | - | - | 0 |
| Sodium | Na | 11 | 11 | 12 | 11 | 2 | 8 | 1 | - | 1 |
| Magnesium | Mg | 12 | 12 | 12 | 12 | 2 | 8 | 2 | - | 2 |
| Aluminium | Al | 13 | 13 | 14 | 13 | 2 | 8 | 3 | - | 3 |
| Silicon | Si | 14 | 14 | 14 | 14 | 2 | 8 | 4 | - | 4 |
| Phosphorus | P | 15 | 15 | 16 | 15 | 2 | 8 | 5 | - | 3.5 |
| Sulphur | S | 16 | 16 | 16 | 16 | 2 | 8 | 6 | - | 2 |
| Chlorine | Cl | 17 | 17 | 18 | 17 | 2 | 8 | 7 | - | 1 |
| Argon | Ar | 18 | 18 | 22 | 18 | 2 | 8 | 8 | 0 | |
Write true or false for the following statement
An atom on the whole has a positive charge.
What are the two main features of Rutherford’s atomic model?
The atomic number and the mass number of sodium are 11 and 23 respectively. What information is conveyed by this statement.
FILL IN THE BLANK
Atomic theory of matter was given by ..........................
Name the particles which actually determine the mass of an atom.
Fill in the blank of the following statement :
The total number of protons and neutrons in the nucleus of an atom is called its _________.
Fill in the blank of the following statement :
All the mass of an atom is concentrated in a small region of space called the ___________.
(a) Which of the nuclear particles is present in the same fixed number in the atoms of any particular element?
(b) What do we call this number which is characteristic of a particular element?
The number of electrons in the atom of an element X is 15 and the number of neutrons is 16. Which of the following is the correct representation of an atom of this element ?
The atom of an element X has 7 electrons in its M shell.
What is the atomic number of element X?
What are orbits or shells of an atom?
Define the term ‘mass number’ of an atom.
State why the atomic weight of an element is also termed relative atomic mass.
The diagram represents an isotope of hydrogen [H]. Answer the following:
Atomic no. = 1
Mass no. = 1
Are isotopes atoms of the same element or different elements.
The diagram represents an isotope of hydrogen [H]. Answer the following:
Atomic no. = 1
Mass no. = 1
If an isotope of ‘H’ has mass no. = 2, how many electrons does it have.
A ______ number describes a specific aspect of an electron.
K and L shells can accommodate a maximum of 2 and 8 electrons respectively.
A group of elements in the periodic table is given below (Boron is the first member of the group and Thallium is the last).
Boron, Aluminium, Gallium, Indium, Thallium
Answer the following question in relation to the above group of elements:
The atomic number of boron is 5. Write the chemical formula of the compound formed when boron reacts with chlorine.
