Dmitri Mendeleev is known for developing a method in 1869 for organizing these.
What are elements?
This is the number of protons in an atom.
What is the atomic number?
These are described as negatively charged particles in an atom.
What are electrons?
Group 1A elements are known for being the most what.
What is reactive?
Although rejected by Aristotle, this Greek philosopher pondered the existence of atoms.
The columns and rows of the Periodic Table are called these.
What are groups and periods?
The sum of protons and neutrons in the nucleus of an atom is this.
What is mass number?
He developed the idea that electrons orbited around the nucleus likes planets do the sun.
Who is Niels Bohr?
These elements have 8 valence electrons, and are thus, non-reactive.
What are the noble gases? What is Group 8A?
He developed the first atomic theory.
Who was John Dalton?
Mendeleev's table is called periodic because it shows this.
What are repeating patterns?
This atom has no neutrons.
What is hydrogen?
This model of the atom assumes that the movement of electrons is less predictable than in Bohr's fixed energy level.
What is the electron cloud model?
Fluorine and chlorine are members of this non-metal yet extremely reactive group.
What are halogens? What is Group 7A?
Rutherford assigned this name to the positively charged particles of atoms.
What is proton?
The objects featured in the periodic table are placed in the rows that shows this increase.
What is an increase in the atomic number? What is an increase in the number of protons?
Atoms of an element with the same number of protons but different numbers of neutrons are this.
What are isotopes?
This term describes the way electrons are arranged in the orbitals in each energy level.
What is electron configuration?
This Group 6A element reacts with just about everything to form new compounds.
What is oxygen?
Rutherford discovered that certain elements emit these fast-moving positively charged particles.
What are alpha particles?
The top number of each block represent this.
What is the atomic number?
Nitrogen-15 is the isotope of the element with this many protons and neutrons.
What are 7 protons and 7 neutrons?
When all of an atom's electrons are in the lowest possible energy levels, it is said to be in this state.
What is the ground state?
This soft-metal element has only one valence electron and thus, will violently react to water so it is stored in oil.
What is sodium?
Arising from the research of Lavoisier, this Law states that Matter cannot be created or destroyed but it can change forms.
What is the Law of Conservation of Mass?