General Science/Everyday Science MCQs
Topic Notes: General Science/Everyday Science
MCQs and preparation resources for competitive exams, covering important concepts, past papers, and detailed explanations.
Plato
- Biography: Ancient Greek philosopher (427–347 BCE), student of Socrates and teacher of Aristotle, founder of the Academy in Athens.
- Important Ideas:
- Theory of Forms
- Philosopher-King
- Ideal State
51
What is the main reason for 'food poisoning' after eating old or improperly stored food?
Answer:
Toxic substances produced by bacteria like Salmonella or Staphylococcus
Food poisoning is often caused by eating food contaminated with bacteria or the toxins they produce while growing on the food. Salmonella and Staphylococcus aureus are common culprits that cause vomiting and diarrhea shortly after ingestion.
52
Which of the following is a characteristic of noble gases?
Answer:
Full outer electron shells
Noble gases (Group 18) are very stable and unreactive because they have a complete valence shell (octet), meaning they have no tendency to gain or lose electrons.
53
Which bond is formed by the sharing of electron pairs between atoms?
Answer:
Covalent
Covalent bonding occurs between non-metal atoms that share one or more pairs of electrons to achieve a stable electron configuration (usually an octet).
54
How many periods are there in the Long Form of the Periodic Table?
Answer:
7
The Periodic Table consists of 7 horizontal rows called periods. The period number corresponds to the highest principal quantum number ($n$) of the electrons in that element.
55
Which model of the atom is often referred to as the 'Plum Pudding' model?
Answer:
Thomson Model
J.J. Thomson proposed that the atom was a sphere of positive charge with negatively charged electrons embedded in it, similar to raisins in a pudding. This was later disproved by Rutherford's gold foil experiment.
56
In the modern periodic table, elements are arranged in increasing order of:
Answer:
Atomic number
Arrangement by atomic number ensures that elements with similar electron configurations fall into the same group, explaining the 'periodicity' of their properties.
57
Common cold and COVID-19 are both respiratory infections. What is a shared characteristic of these diseases?
Answer:
They are both caused by viruses
Both the common cold (often caused by rhinoviruses) and COVID-19 (caused by the SARS-CoV-2 virus) are viral infections. Because they are viruses, they spread through droplets and do not respond to antibiotic treatment.
58
What is the maximum number of electrons that can occupy the first energy level (K-shell) of an atom?
Answer:
2
The maximum number of electrons in any shell is given by the formula $2n^2$, where $n$ is the shell number. For the first shell ($n=1$), the maximum is $2(1)^2 = 2$ electrons.
59
As we move from top to bottom in Group 1, the reactivity of metals:
Answer:
Increases
Reactivity in metals is the ease with which they lose electrons. Down Group 1, atomic size increases and ionization energy decreases, meaning Potassium is more reactive than Sodium because it loses its valence electron more easily.
60
The nucleus of an atom consists of which particles?
Answer:
Protons and neutrons
The nucleus is the small, dense region consisting of protons and neutrons at the center of an atom. These particles are collectively known as nucleons and are held together by the strong nuclear force.