Periodic table
What is the atomic number of carbon?
6
What is the formula for calculating density?
Density = Mass ÷ Volume
What are the three main subatomic particles in an atom?
Protons, neutrons, and electrons
Who is known as the father of modern atomic theory?
John Dalton.
What does the Kinetic Molecular Theory explain?
The behavior of gases based on particle motion.
Which element has the chemical symbol "Na"?
Sodium
An object has a mass of 200 grams and a volume of 50 cm³. What is its density?
4 g/cm³
(Density = 200 ÷ 50 = 4)
What is the charge of a proton?
Positive (+1)
What did Dalton's atomic theory state about atoms of the same element?
That all atoms of the same element are identical in mass and properties.
What are gas particles like according to K.M.T?
Small, hard spheres with no volume.
What is the name of the group 18 elements in the Periodic Table?
Noble gases
If an object has a density of 2.5 g/cm³ and a volume of 10 cm³, what is its mass?
(Mass = Density × Volume = 2.5 × 10 = 25)
Where are protons and neutrons located in an atom?
In the nucleus at the center of the atom.
What did Rutherford’s gold foil experiment show?
Atoms have a small, dense, positive nucleus.
How do gas particles move?
In constant, random, straight-line motion.
Who is credited with creating the first version of the Periodic Table?
Dmitri Mendeleev
A rock has a density of 3 g/cm³ and a mass of 600 grams. What is its volume?
200 cm³
(Volume = Mass ÷ Density = 600 ÷ 3 = 200)
Which subatomic particle determines the atomic number of an element?
The proton.
What did Bohr’s model suggest?
Electrons orbit the nucleus in fixed energy levels.
What happens when gas particles collide?
Collisions are elastic—no energy is lost.
Which is the lightest element on the Periodic Table?
Hydrogen
True or False: If two objects have the same volume, they must have the same density.
False
(Density also depends on mass, not just volume.)
What is the charge of an electron?
Negative (-1).
What does the modern atomic theory say?
Electrons exist in probability clouds, not fixed paths.
How does temperature affect gas particle motion?
Higher temperature means faster particle movement.