🔥🔥🔥Chemistry UNIT 1 QUESTION


1. Who proposed the planetary model of the atom?
a) Ernest Rutherford
b) Niels Bohr
c) J.J. Thomson
d) James Chadwick

2. Which subatomic particle has a positive charge?
a) Electron
b) Proton
c) Neutron
d) Nucleus

3. What is the approximate mass of an electron?
a) 1 atomic mass unit (amu)
b) 1/2 atomic mass unit (amu)
c) 1/1836 atomic mass unit (amu)
d) 1836 atomic mass units (amu)

4. Which of the following is NOT a fundamental particle?
a) Quark
b) Lepton
c) Photon
d) Neutrino

5. Who discovered the existence of neutrons?
a) Ernest Rutherford
b) Niels Bohr
c) J.J. Thomson
d) James Chadwick

6. What is the maximum number of electrons that can occupy the first energy level of an atom?
a) 2
b) 4
c) 8
d) 16

7. What is the charge of an atom that has gained two electrons?
a) -1
b) -2
c) +1
d) +2

8. What is the atomic number of an atom?
a) The number of protons in the nucleus
b) The number of electrons in the nucleus
c) The total number of protons and neutrons in the nucleus
d) The total number of electrons in the atom

9. What is an isotope?
a) An atom with a different number of neutrons
b) An atom with a different number of protons
c) An atom with a different number of electrons
d) An atom with a different number of energy levels

10. Which of the following best describes the electron cloud model?
a) Electrons are arranged in discrete energy levels around the nucleus.
b) Electrons are located in specific orbits around the nucleus.
c) Electrons are spread out in a cloud-like region around the nucleus.
d) Electrons are confined to specific regions within the nucleus.

Answers:
1.  b) Niels Bohr
2.  b) Proton
3.  c) 1/1836 atomic mass unit (amu)
4.  c) Photon
5.  d) James Chadwick
6.  a) 2
7.  b) -2
8.  a) The number of protons in the nucleus
9.  a) An atom with a different number of neutrons
10.  c) Electrons are spread out in a cloud-like region around the nucleus.


         
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Grade 🔟
Subject chemistry 🧪
unit 2⃣

1. Which of the following is not a  
   characteristic property of acids?
   A) Sour taste
   B) Ability to turn litmus paper red
   C) Reactivity with metals to 
        produce hydrogen gas
   D) Slippery feel

2. Which of the following is a strong acid?
   A) PH3
   B) CH3COOH
   C) HClO4
   D) HNO2

3. What happens when an acid reacts with a base?
   A) Formation of hydrogen gas
   B) Formation of water and a salt
   C) Increase in pH
   D) Decrease in temperature

4. Which of the following cannot act as an acid?
   A) HCl
   B) NaOH
   C) H2SO4
   D) H2CO3

5. Which of the following represents a weak base?
   A) NaOH
   B) NH3
   C) KOH
   D) Ca(OH)2

6. Which pH value indicates a strong acid?
   A) 2
   B) 7
   C) 10
   D) 14

7. What is the chemical formula for hydrochloric acid?
   A) HNO3
   B) H2SO4
   C) HCl
   D) HClO3

8. Which of the following is a common household base?
   A) Vinegar
   B) Lemon juice
   C) Ammonia
   D) Orange juice
9. What is the concentration of hydrogen ions in a solution with a pH of 3?
    A) 1 x 10^-7 M
    B) 1 x 10^-3 M
    C) 1 x 10^-11 M
    D) 1 x 10^3 M

Answers:
1. D) Slippery feel
2. C) HClO4
3. B) Formation of water and a salt
4. B) NaOH
5. B) NH3
6. A) 2
7. C) HCl
8. C) Ammonia
9. B) 1 x 10^-3 M
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