L3

Question 1

In a chemical reaction, no change in mass takes place. The total mass of the products is equal to the total mass of the reactant

Answer 1

Law of conservation of mass

Question 2

A compound always contains the same constituent elements in a fixed or definite proportion by mass

Answer 2

Law of definite proportions

Question 3

If two elements A and B combine to form more than one compound, the masses of B that can combine with a given mass of A are in the ratio of small whole numbers

Answer 3

Law of Multiple Proportions

Question 4

A brilliant French Chemist who formulated Law of conservation of mass

Answer 4

Antoine Lavoisier

Question 5

It is said that mass is neither created nor destroyed in ordinary chemical and physical changes

Must start and end with the same amount

Answer 5

Law of conservation of mass

Question 6

This Theory states

1.each element is composed of extremely small particles called atoms

2.all atoms of a given element are identical, but the atoms of one element are different from the atoms of all other elements

3. Atoms of one element cannot be changed into atoms of a different element by chemical reactions; atoms are neither created nor destroyed in chemical reactions

Answer 6

Daltons Atomic theory

Question 7

Atoms are dense and solid, with no internal structure or subatomic particles considered

Person involved?

Answer 7

Solid sphere 1803

John Dalton

Question 8

Atoms are described as uniform. Positively charged spheres with electrons embedded within them, similar to raisins in a pudding

Person Involved?

Answer 8

Plum pudding 1897

JJ Thomson

Question 9

Atom consists of a small, dense, positively charged nucleus at the center, with electrons orbiting around it. Similar to planets orbiting around the sun

Person involved

Answer 9

Nuclear 1911

Ernest Rutherford

Question 10

Atom consists of a small, dense, positively charged nucleus at the center, with electrons orbiting around it. Similar to planets orbiting around the sun

Person involved

Answer 10

Nuclear 1911

Ernest Rutherford

Question 11

Electrons move in quantized, discrete energy levels around the nucleus and emit or absorb energy when transitioning between levels

Answer 11

Planetary 1913

Niels Bohr

Question 12

Electrons do not have definite orbits, but are described by wave functions that represent probability distributions of their locations

Answer 12

Quantum 1920

Erwin Schrodinger

Question 13

Atoms are tiny balls that Can’t be broken and are all made of the same material. This theory helps explain how different chemicals mix together and what makes them different

Answer 13

Solid sphere model

Question 14

Who discovered electrons as distinct particles

Answer 14

J.J Thomson

Question 15

According to this Theory, atoms are like plum pudding with tiny positive charges scattered throughout a cloud of negative electrons. This Theory helped explain why atoms have a neutral charge overall and why they emit light when they collide with each other

Answer 15

Plum pudding model

Question 16

New Zealand-born physicist known for his contributions to nuclear physics.

First model to propose a central, massive nucleus

Answer 16

Ernest Rutherford

Question 17

According to this theory, atoms have a nucleus with a positive charge and most of the mass, surrounded by electrons that orbit like planets. It explains why particles can pass through or bounce off atoms, and is the basis of our current understanding of atomic structure

Answer 17

Nuclear Model

Question 18

Danish physicist known for his pioneering work in atomic structure

Explained atomic spectra with precision

Answer 18

Niels Bohr

Question 19

According to this theory, electrons orbit the nucleus of an atom in specific energy levels or shells. This theory helped explain why atoms emit light and why they absorb certain colors of light. It also helped explain the stability of atoms and why they don’t fall apart

Answer 19

Planetary model

Question 20

Austrian physicist renowned for his contributions to quantum mechanics
(Understanding electron behavior)

Answer 20

Erwin Schrodinger

Question 21

According to this theory, electrons exist as a probable wave like pattern around the nucleus, not in a specific orbit. It explains why electrons act like particles and waves, and is the foundation of our understanding of atomic structure and widely used in modern physics

Answer 21

Quantum model