ATOMIC STRUCTURE AND BONDING IN SOLIDS part 1 Flashcards
What is atomic structure?
Atomic structure refers to the structure of an atom.
What is an atom’s structure?
An atom is made up of a center of positive charges called protons and none charges called neutrons, called the nucleus. negative charged called electrons revolve around the nucleus.
what group of particles do protons and neutrons fall under?
nucleon
electrons and protons have opposing charges of the same magnitude. true or false?
true!
what is the charge of an electron?
1.60x10^-19 coulombs
protons and neutrons have roughly equivalent masses of ~1.67x10^-27 but which is heavier?
neutrons
what is atomic number?
the number of protons in a nucleus
when is an atom neutral ?
when the number of proton is equal to the number of electrons
atoms of the same element can have the same number of protons but different neutron number. true or false
true
He^4
2
how many protons, neutrons and electrons are there in this element?
2 protons
2 neutrons
2 electrons
how did you find the protons?
how did u find the electrons?
how did u find the neutrons?
the protons are the same as the atomic number the bottom number.
the number of electrons is the same as the number of protons.
the number of neutrons is equal to the mass number(the number at the top) - the proton (atomic) number.
what are isotopes?
are the same element that have different atomic mass numbers due to different number of neutrons.
what are the two atomic model
Bohr atomic model and
Wave-mechanical model
what is a bohr atomic model
Bohr atomic models are scientist early attempt to describe the position and energy level of electrons in an atom. But it does not help example several phenomena involving electrons as it is to simplistic.
Describe the characteristics of a Bohr atomic model
-Electrons revolve around an atomic nucleus in discrete orbitals.
- the position of any electron is defined in terms of its orbital
- Electrons have quantized/ specific energy levels
- electrons absorb energy in terms of photons when it makes a quantum jump to a higher energy level and emits energy when jumping to a lower energy level
-the energy of a photon is planks constant (h) * frequency of the proton.
describe wave mechanical model
in a wave mechanical model electrons exabit both wave-like and particle-like characteristic.
the position of any electrons is calculated by the probability of it being at various location around the nucleus this is call probability distribution or an electron cloud
Principle quantum number (n)
refers to the distance from the nucleus. n 1 being the closest
secondary quantum number (l)
relates to the shape of the subshell. has letters s,p,d,f and it is limited by the value of n
third quantum number (ml)
specifies the number of energy states for each subshell. s = 2, p= 6, d= 10, f= 14 and can go to infinity.
fourth quantum number(ml)
specifies the spatial orientation for each electron’s spin moment (up or down) +1/2 or -1/2
Pauli exclusion principle
This states that in an atom or molecule no two electrons can have the same four electronic quantum numbers( they can not take up the same position).
and each electron in the same orbital must have opposing spins.
this principle is used to determine the manner in which electrons are filled into shells
what is ground state?
an atom is in its ground state when all electrons occupy the lowest possible energy levels
what are valence electrons
these are electrons that occupy the outer most shell.
these outer most electrons participate in interatomic bonding and affect the physical and chemical properties of solids
when does an atom achieve stability and how does it achieve this
when the atom has completely filled valence electron shells. it ca achieve this by losing or gaining electrons to form charged ions or by sharing electrons with other atoms
state the electron configurations of
- k
- fe
-fe3+
k = 19
1s2 2s2 2p6 3s2 3p6 4s1
fe = 26
1s2 2s2 2p6 3s2 3p6 4s2 3d6
fe3+
1s2 2s2 2p6 3s2 3p6 3d5
F, CL ,BR,I , AT are a group of elements known as
Halogens
group 1 metals are known as
alkali metals
group 2 metals are known as
alkali earth metals
what is a transition element?
this is a d block element that forms one or more stable ions with complete d subshells
what is an electro positive element
not all elements that lose electrons are metals thus we give the term for all elements that gain stability by the lose of electrons to form positively charged ions a electro positive
what is an electro negative element
these are elements that have to gain electrons in order to gain stability by forming negatively charged ions Or by sharing electrons with other atoms as electro negative
electronegativity increases across a group and up a period true or false?
true
what factors do valence electrons determine in atomic bonding?
-chemical
-optical
-electrical
-thermal
what is bond energy in terms of attractive forces and repulsive forces formula?
En (net energy) = EA(attractive) + ER(replusive)
