History
Who proposed that matter is made of tiny indivisible particles called atomos?
Democritus
What subatomic particle has a positive charge?
Proton
If an atom has an equal number of protons and electrons, what is its net charge?
NEUTRAL
Which isotope of hydrogen has one neutron?
Deuterium (Hydrogen-2)
Boron occurs naturally as 19.9% Boron-10 (10.013 amu) and 80.1% Boron-11 (11.009 amu). What is the average atomic mass of boron?
11 amu
Which scientist proposed the Plum Pudding Model?
J.J. Thomson
What is the name of a subatomic particle without an electrical charge?
Neutron
An atom has 12 protons, 12 neutrons, and 12 electrons. What is its atomic number?
12
Which isotope is commonly used to determine the age of ancient fossils and archaeological artifacts?
Carbon-14 (C-14)
Chlorine has two naturally occurring isotopes: 75.77% Cl-35 (34.969 amu) and 24.23% Cl-37 (36.966 amu). Calculate its average atomic mass.
35 amu
Which experiment led Rutherford to discover the nucleus?
Gold Foil Experiment
What subatomic particle moves around the nucleus in orbitals?
Electrons
An ion has 17 protons and 18 electrons. What is its net charge?
-1
Which isotope is used in hospitals to diagnose and treat disorders of the thyroid gland?
Iodine-131 (I-131)
Copper exists as 69.17% Cu-63 (62.930 amu) and 30.83% Cu-65 (64.928 amu). What is the average atomic mass of copper?
64 amu
What was the name of the atomic model made by Niels Bohr?
Planetary Model
Where are protons and neutrons located in an atom?
At nucleus
A sodium ion (Na⁺) has 11 protons and 10 electrons. How many neutrons does it have if its mass number is 23?
12 neutrons
Which isotope is widely used in radiation therapy to treat cancer?
Cobalt-60 (Co-60)
Cesium-137
Magnesium has three isotopes: 78.99% Mg-24 (23.985 amu), 10.00% Mg-25 (24.986 amu), and 11.01% Mg-26 (25.983 amu). Calculate its average atomic mass.
24 amu
Which scientist proposed the Quantum Mechanical Model of the atom?
Erwin Schrödinger
Which scientist discovered the neutral subatomic particle in 1932?
James Chadwick
An iron ion Fe+3 has 26 protons and 30 neutrons. How many electrons does this ion have?
23 electrons
Which isotope is used to detect blood clots and tumors?
Sodium-24 (Na-24)
Neon consists of 90.48% Ne-20 (19.992 amu), 0.27% Ne-21 (20.994 amu), and 9.25% Ne-22 (21.991 amu). Determine the average atomic mass of neon.
20 amu