Atoms Flashcards
What are atoms?
Atoms are the tiny building blocks of all substances.
How small is an atom compared to everyday objects?
A 50p piece contains about 77,400,000,000,000,000,000 atoms.
What do atoms contain?
Atoms contain protons, neutrons, and electrons.
Where is the nucleus located in an atom?
The nucleus is located in the middle of the atom.
What does the nucleus contain?
The nucleus contains protons and neutrons.
What is the radius of the nucleus?
The nucleus has a radius of about 1 x 10-14 m (around 1/10,000 of the radius of an atom).
What charge does the nucleus have?
The nucleus has a positive charge because of the protons.
Where is most of the atom’s mass concentrated?
Almost the whole mass of the atom is concentrated in the nucleus.
Where are electrons located?
Electrons move around the nucleus in electron shells.
What charge do electrons have?
Electrons are negatively charged.
How does the size of electrons compare to protons and neutrons?
Electrons are tiny and have virtually no mass.
What determines the size of the atom?
The volume of the electrons’ orbits determines the size of the atom.
What is the relative mass and charge of a proton?
Relative mass = 1, Charge = +1
What is the relative mass and charge of a neutron?
Relative mass = 1, Charge = 0
What is the relative mass and charge of an electron?
Relative mass = Very small (often taken as zero), Charge = -1
Why are atoms neutral?
Atoms are neutral because they have an equal number of protons and electrons.
What happens to an atom’s charge if it gains or loses electrons?
If the number of protons doesn’t equal the number of electrons, the atom has an overall charge and becomes an ion.
What does it mean if an atom has a 2- charge?
It means the atom has gained two extra electrons.
What does the atomic number tell us?
The atomic number tells us the number of protons and electrons in an atom. (Which are always the same in an atom).
What does the mass number tell us?
The mass number tells us the total number of protons and neutrons in an atom.
How do you find the number of neutrons in an atom?
Subtract the atomic number from the mass number to get the number of neutrons.
What is a nuclear symbol?
A nuclear symbol represents an atom with its atomic (proton and electron) number and mass number (protons and neutrons).
Q1: An atom of gallium has an atomic number of 31 and a mass number of 70. How many protons, neutrons, and electrons does it have?
Protons = 31, Neutrons = 39 (70 - 31), Electrons = 31 (assuming it’s neutral).
