Module 2.1.1 - Atomic structure and isotopes Flashcards
What are the charges and relative masses of the subatomic particles?
Neutron - 0:1
Proton:+1:1
Electron:-1:0(negligible)
Why is an atom neutral?
Contain the same number of protons as electrons, charges cancel out
What does the current model of the atom look like? (5)
- Protons and neutrons in the nucleus
- Electrons orbit in shells outside
- Nucleus is tiny compared to the total volume of an atom
- Most of atom’s mass is in the nucleus
- Most of the atom is empty space between nucleus and electrons
What does the atomic number in periodic table show?
Number of protons in the nucleus of the atom (+electrons in the outer shells)
What does the mass number show in the periodic table?
Number of protons and neutrons in the nucleus
What is an isotope?
Isotopes are atoms of the same element (same number of protons and electrons) with different number of neutrons
Why do different isotopes of the same element react in the same way?
Neutrons do not have any impact on reactivity as reactions involve electrons
What are the differences between isotopic atoms of the same element? (3)
- different masses
- different numbers of neutrons in the nucleus
- different physical properties
What are ions?
Charged particles that are formed when an atom of an element loses/gains electrons (different number of protons:electrons)
What is relative isotopic mass?
The relative isotopic mass is the mass of an atom of an isotope compared with 1/12 of the mass of an atom of carbon-12
What is the relative isotopic mass the same as?
The mass number
What is relative atomic mass?
The weighted mean mass of an atom of an element compared with 1/12 of the mass of an atom of carbon-12.
What does the weighted mean mass account for? (2)
-The percentage abundance of each isotope
-the relative mass of each isotope.
How do you work out relative atomic mass?
(X * X%) + (Y * Y%) / 100 (where X and Y are different isotopes)
