10 Questions
What does the atomic number of an atom represent?
The number of protons in the nucleus
How are elements organized on the periodic table?
By atomic mass
What is the basis for the atomic mass of an element?
The number of protons and neutrons in the nucleus
How was the first version of the periodic table organized?
By atomic mass
What is the role of protons in determining the atomic number?
They are positively charged particles in the nucleus
Who confirmed the existence of protons?
Henry Moseley
How is the modern periodic table arranged?
By atomic number
What defines the identity of an atom?
Number of protons
What changes during nuclear decay?
Atomic number
What stays the same for ions?
Atomic number
Study Notes
- Mendeleev's periodic table was published in 1869.
- English researcher Henry Moseley confirmed the existence of protons in the early 20th century.
- Atomic number is the number of protons in an atom, defining its identity.
- Nuclear decay can result in a change of atomic number, as seen in Uranium-238 becoming Thorium-234.
- Modern periodic table is arranged by atomic number.
- Atomic symbols are abbreviated and may have subscripts and superscripts indicating mass and atomic number.
- Neutral atoms have equal number of protons and electrons, while ions do not.
- Atomic number remains the same for ions, with symbols indicated by a charge symbol as a superscript.
- Isotopes have the same atomic number but different mass numbers due to different neutron counts.
Test your knowledge about atomic numbers, which represent the number of protons in an atom's nucleus. Learn about the unique atomic numbers of elements on the periodic table and their significance in defining an element's properties.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
