A
Which scientist discovered the electron in 1897 using cathode ray tubes?
JJ Thomson
What did the Gold Foil Experiment prove about the atom, leading to the Nuclear Model?
Nucleus
Is plain water an example of a pure substance or a mixture?
Pure substance
Which ancient Greek philosopher is credited with first proposing the idea of tiny, indivisible particles called "atomos"?
Democritus
A type of mixture where the parts are completely blended and look the same throughout (like salt dissolved in water) is called what kind of mixture?
Homogeneous
Who is widely considered the "father" of the modern periodic table for his arrangement of elements in 1869?
Dmitri Mendeleev
Which type of pure substance is found on the Periodic Table?
Elements
Who proposed the early atomic theory that stated all matter is made of indivisible atoms?
John Dalton
What are the three main tiny particles that make up an atom?
Protons, electrons, and neutrons
The elements in the modern periodic table are arranged in order of increasing what?
Atomic number
A neutral atom has a mass number of 35 and an atomic number of 17. Calculate the number of protons in this atom.
17
An isotope of Potassium has 19 protons and 21 neutrons. Determine its mass number
40
Name the family of nonmetal elements that are generally unreactive with 8 valence electrons.
Noble gases
Type of orbitals which can handle maximum of 14 electrons.
F orbit
Number of shell present in Period 6.
6
A chemist is developing a new compound and needs an element with properties similar to Calcium (Ca) which is in Group 2A. In which group would she look, knowing that elements in the same vertical column often exhibit similar chemical reactivity?
Alkali metals
If a scientist is observing the distinct colors of light emitted when certain gases are excited (like in neon signs or fireworks), this phenomenon provides evidence for which atomic model that introduced specific energy levels or electron shells?
Sodium (Na) and Lithium (Li) both react strongly with water. This similar chemical behavior is primarily due to their location in Group 1, which means they both have ________________.
Valence electron or chemical properties
An element is known to have an electron configuration of 1s2 2s2 2p6 3s2. How many valence electrons does this element have?
2
What are the 6 metalloids?
Boron, Silicon, Germanium, Arsenic, Antimony, and Tellurium