9th GRADE CHEMISTRY QUIZ - 04.01.2021

X^1- ion has 9 more neutrons than electrons, and its atomic number is 35. What is the atomic mass number of X ?

• 40

• 70

• 79

• 80

• 81

Which of the following properties and numbers can change for an atom while forming a compound?

I. Proton number

II. Atomic mass number

III. Electron number

IV. Chemical properties

• Only III

• II and III

• II , III and IV

• III and IV

• I , II , III and IV

₁₂X²⁺ ion and Y^2- ion have same number of electrons. What is the nucleus charge of Y?

• 14

• 12

• 10

• 9

• 8

Which of the followings is false for an ion that has 21 protons, 18 electrons and 24 neutrons?

• The nucleus charge is 21.

• Atomic mass number is 45.

• Ionic charge is -3 .

• Atomic number is 21

• The total subatomic particle number is 63 .

Which of the following scientists was the discoverer of the positively charged nucleus in his atomic model?

• Dalton

• Thomson

• Rutherford

• Bohr

• Chadwick

Which of the following statements are false for Bohr's Atomic Model?

I. Electrons move on fixed energy levels.

II. Electrons gain energy when they turn back from higher energy levels to lower energy levels.

III. Atoms are stable in their ground states.

• Only I

• Only III

• I and II

• I and III

• I , II and III

Which of the followings are true for Dalton's atomic model?

I. Atoms cannot be divided.

II. Different elements have different atoms.

III. Atoms have protons and neutrons.

• Only I

• I and II

• I and III

• II and III

• I , II and III

Which of the followings is not a discovery that was discovered during alchemy and is used in chemistry also?

• Glass production

• Analysis of blood sample

• Paints

• Ink production

• Making alloys from metals

Which of the following element symbols is written wrong?

• Carbon : C

• Phosphorous : F

• Nitrogen : N

• Helium : He

• Gold : Au

Which of the following common name of compounds is written wrong?

• NH₃ : Ammonia

• HNO₃ : Vitriol (Aqua Fortis)

• H₂SO₄ : Oil of vitriol

• HCl : Spirit of salt

• Ca(OH)₂ : Unslaked lime