Journey Inside the Atom
Class 9 · Science · 42 Questions
Suppose you made up your own 'atom', as Thomson described, using clay for the positive charge and small beads for the electrons spread through it. What will happen if:
Could an orange or a lemon, which also contain seeds inside soft pulp, be a good comparison? In what ways does it match Thomson’s idea and where does it fall short?
Why did Thomson conclude that electrons are present in all atoms?
Can you calculate how many atoms would be needed to make a sheet of paper that is 0.1 mm thick, like the one in your textbook?
What do you think would happen if α-particles were replaced with negatively charged particles in Rutherford’s gold foil experiment?
Rutherford found that a few α-particles bounced back sharply. How does this single surprising result completely rule out Thomson’s ‘plum pudding model’ of the atom?
If you could ask Rutherford one question about his work, what would it be?
Assertion (A): Rutherford concluded that most of the mass of an atom is concentrated in a small region at the centre called the nucleus. Reason (R): According to Thomson’s model, electrons are embedded in a uniformly distributed positive charge sphere.
What if an atom had no empty space? How would this have affected the size of various objects?
Imagine you are a scientist who has discovered a new element. Name this element after yourself and justify that the symbol you have chosen follows the IUPAC rules.
What problems could arise if every scientist used different symbols for the same element?
An atom with an atomic number of 26 has 56 nucleons. Find out its number of electrons, protons and neutrons.
The nucleus of an atom contains 20 protons. If its mass number is 41, find the number of neutrons in it.
An atom has 18 neutrons and an atomic number of 17. What is its mass number?
An atom 23A has 11 electrons. Find the number of neutrons in it.
Helium contains two protons in its nucleus and two electrons. In which way will the two electrons be arranged in its atomic shell?
Identify the number of electrons in the outermost shell of the following elements:
Write the electronic configuration of the elements having atomic numbers 12, 16 and 18.
Solve this riddle: I am an atom with a mass number of 23 and 11 protons. I am a soft metal and react vigorously with water. Who am I and how many neutrons do I have? You can also create one such riddle.
In NH3 (ammonia) and MgCl2 (magnesium chloride), what will be the combining capacities of nitrogen and magnesium respectively?