1.1 Atomic Structure Flashcards
What is all matter composed of?
Atoms
What are atoms?
The smallest parts of an element that can take place in chemical reactions
What is the structure of an atom?
Atoms are mostly made up of empty space around a very small, dense nucleus that contains protons and neutrons
What are protons and neutrons sometimes referred to as?
Nucleons
What charge does the nucleus of an atom have?
Overall positive charge
Why does the nucleus have a positive charge?
Because protons have a positive charge and neutrons have a neutral charge
Where are negatively charged electrons found?
In orbitals in the empty space around the nucleus
What are subatomic particles?
The particles an element is made up of, including protons, neutrons, and electrons
Can the masses and charges of subatomic particles be measured using conventional units?
No, they are compared using ‘relative atomic masses’ and ‘relative atomic charges’
What are relative atomic masses and charges?
Charges and masses of particles relative to each other, not actual charges and masses
What relative mass is assigned to protons and neutrons?
1
How much smaller is an electron compared to a proton or neutron?
1836 times smaller
What are the charges of protons, electrons, and neutrons?
- Protons: positively charged
- Electrons: negatively charged
- Neutrons: neutral
What is the atomic number (Z)?
The number of protons in the nucleus of an atom
What does the atomic number equal in a neutral atom?
The number of electrons present
What is the atomic number of lithium?
3
What is the mass number (A)?
The total number of protons and neutrons in the nucleus of an atom
How can the number of neutrons be calculated?
Number of neutrons = mass number - atomic number
What are protons and neutrons also called?
Nucleons
