Advertisements
Advertisements
Question
Draw the structure of the following atoms showing the nucleus containing – protons, neutrons and the orbits with the respective electron:
Silicon [At. no. = 14, Mass no. = 28]
Advertisements
Solution
Structure of atoms:
Z is Atomic Number and A is the mass number
Silicon \[\ce{^28_14Si}\]
Z = 14 = p = e
K L M
e = 14 = 2, 8, 4
A = p + n
28 = 14 + n
∴ n = 28 − 14 = 14
APPEARS IN
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 | |
What is variable valency? Name two elements having variable valency and state their valencies.
The mass number of an element is 23 and it contains 11 electrons. What is the number of protons and neutrons in it? What is the atomic number of the element?
Elements X, Y, Z have atomic numbers 6, 9 and 12 respectively. Which one:
- forms anion – negative ion;
- forms cation – positive ion;
- has 4 electrons in the outermost orbit. [Y, Z, X]
The atomic number of an element is 9, it has 10 neutrons. Find the element from the periodic table. What will be its mass number?
Name the 3 sub-atomic particles of an atom.
Mass No. 27 is for the element ______.
Match the following:
| Column A | Column B | ||
| 1. | K shell | a. | 8 |
| 2. | L shell | b. | 32 |
| 3. | M shell | c. | 2 |
| 4. | N shell | d. | 18 |
Match the following:
| Column A | Column B | ||
| 1. | Mass of proton | a. | +1 |
| 2. | Mass of electron | b. | -1 |
| 3. | Charge of electron | c. | 9.31 x 10-28g |
| 4. | Charge of proton | d. | 1.67 x 10-24g |
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.
