Atoms Test (1/2025) Flashcards
What is the nucleus?
At the center of the atom is a tiny dense nucleus that carries protons and neutrons.
What are protons?
Positively charged particles. The amount of protons is the atomic number.
What are neutrons?
Neutrons are neutral particles meaning they have no charge.
What are electrons?
Negatively charged particles.
Where are electrons found?
On an orbit around the nucleus. When they have a lower energy level they are closer to the nucleus. If it has a higher energy level, the electrons are found further away from the nucleus.
What is the mass number?
Protons and neutrons combined mass.
What is the atomic number?
Number at the top of a periodic table entry (number of protons)
What is the atomic mass/weight?
Number at bottom of periodic table entry (weighted average mass of all isotopes of an element) Found as a decimal number.
What are isotopes
When the same element has different atoms with different numbers of neutrons.
What is an electrons mass
1/1840 AMU *not counted when finding the mass of the atom.
What is a neutron’s mass?
1 AMU
What is a protons mass?
1 AMU
What is the Atomic symbol?
The letter on the periodic table.
What is a neutral atom?
An atom with the same amount of protons and electrons.
How do you find the number of neutrons in the most common isotope?
Round the atomic number to the nearest whole number, then look at the atomic number to determine the number of protons, then subtract the number of protons from mass number, and the number left over is the number of neutrons
