Unit 1: Section 1- Atomic Structure Flashcards
What is the relative mass and charge of an electron?
1/1840 and -1
What is the difference between mass number and atomic number?
Atomic number= number of protons
Mass number= total number of protons and neutrons
How do you work out the number of neutrons in an element?
subtract the atomic number from the mass number
Define isotope
an isotope of an element is an atom with the same number of protons but a different number of neutrons
Explain the differences and similarities of different isotopes and their chemical and physical properties
Isotopes of an element have the same electronic configuration, and therefore have similar chemical properties. However, their physical properties may vary due to the difference in mass.
How are electrons arranged?
principle energy levels (1,2,3,4) , sub- energy levels (s,p,d,f) and orbitals
What is the trend in principle energy levels as you move away from the nucleus?
Principle energy levels increase in energy as you move away from the nucleus.
What block are group 1 and 2 elements found in?
s
What block are group 3 elements found in?
p
What elements are found in block d?
transition metals
Where can the f-block be found?
below the periodic table
What shape is the s-orbital?
spherical
How many orbitals does the s subshell have?
1
How many orbitals does the p subshell have?
3
How many orbitals does the d subshell have?
5
How many orbitals does the f subshell have?
7
Why does the 4s subshell fill before the 3d subshell?
The 4s subshell fills before the 3d subshell because the 4s subshell is lower in energy than the 3d subshell.
What happens when elements in the d-block form positive ions?
the electrons are removed from the 4s subshell before the 3d subshell.
What is noble gas configuration used for?
to avoid long configurations, find the noble gas from the previous period, then write out the rest of the configuration
Why do electrons favour half or fully filled d subshells?
because of the symmetrical distribution of electrons
Name and explain two examples of elements with electron arrangements that favour the half or fully filled d subshell
Chromium, Copper
For chromium, the 3d subshell is made to be half full leaving the 4s subshell with only one electron. Similarly, for copper, the 4s subshell is left with only one electron to allow for the 3d subshell to be completely full.
How do you fill subshells when drawing spin diagrams?
When filling up subshells, fill in each orbital with one electron before beginning to pair them up. This is because electrons first enter the orbitals that are empty before filling singularly occupied orbitals.
Define ionisation energy
the enthalpy change when one mole gaseous atoms form gaseous ions with positive charges
Define first ionisation energy
the enthalpy change when one mole of gaseous atoms forms one mole of gaseous ions with a single positive charge.
Define second ionisation energy
the enthalpy change when one mole of gaseous ions with a single positive charge forms one mole of gaseous ions with a double positive charge
Name three factors that effect ionisation energy
- nuclear charge
- size of the atom
- shielding
Why does nuclear charge effect ionisation energy?
the more protons in the nucleus the greater the nuclear charge and the greater the attraction of the electrons to the nucleus.
Why does the size of the atom effect ionisation energy?
the outer shell of bigger atoms will be further from the nucleus so there would be a weaker attraction between the nucleus and the electrons