Periodic Table & Periodicity of Properties Flashcards
who discovered atomic number?
Moseley
what are the horizontal rows called in the periodic table?
periods
what are the vertical columns called in the periodic table?
group or family
what are the first three periods called?
short periods
what are group A elements called?
Representative elements
what are group B elements called?
Transition elements
periodic table is arranged according to ___________?
increasing atomic no.
number of protons
why He is not placed after H?
He has different chemical properties & has to be grouped accordingly
if group of elements have same chemical properties then what is similar?
they have same valence electrons which = same chemical properties & that’s why are grouped in a group/family
majority of element in the periodic table are _______?
metals
minority of element in the periodic table are _______?
non-metals
is H metal or non-metal
non-metal
Group IA elements are called?
alkali metals
what group of elements is called halogens?
7th group
group VIIA elements are called?
halogen
group VIIIA elements are called?
noble gases
elements that have similar chemical properties lie in the same ______ in the periodic table.
column/group
how many periods are there in the periodic table?
7
how many groups are there in the periodic table?
18
8
what does the period tell us?
no. of shells
what does the group tells us?
no. of valence electrons in an element
group IA and group IIA elements are called?
s-block elements
group IIIA to group VIIIA elements are called?
p-block elements
(except He)
what is a metalloid?
Metalloids, also known as semimetals, are a group of elements that exhibit properties that are intermediate between metals and nonmetals. They are located along the diagonal “staircase” region on the periodic table, separating the metals on the left from the nonmetals on the right.
name metalloids?
8
Boron (B)
Silicon (Si)
Germanium (Ge)
Arsenic (As)
Antimony (Sb)
Tellurium (Te)
Polonium (Po) (optional)
Astatine (At)
what is shielding effect
reduction in the attractive force between the +vely charged nucleus of an atom and its valence e- by the e- present in the inner shells.
The shielding effect is the __________ in the attractive force between the nucleus and the outer electrons due to the presence of inner electrons.
reduction
The shielding effect results in a __________ effective nuclear charge experienced by the outermost electrons compared to the actual charge of the nucleus.
reduced
The shielding effect causes larger atomic sizes because the outermost electrons are held __________ tightly by the nucleus.
less
Moving down a group in the periodic table, the shielding effect __________
increases
The shielding effect primarily affects which atomic property?
Atomic size
what is the size of an atom?
average distance between the nucleus and the valence shell.
as you move across the period, the atomic radius _________?
decreases
as you move down a group, the atomic radius _________?
increases
why the atomic radius decreases across a period?
The increase in nuclear charge attracts the electrons more strongly, pulling them closer to the nucleus.
moving across a period, the shielding effect __________
remains constant
cations are +ve ion that _______ electrons?
lose
cz it has more protons than electrons
anions are -ve ion that _________ electrons?
gain
cz it has more electrons than protons
group IVA loses/gains __________ electrons.
lose
+4
group VIIA loses/gains __________ electrons.
gains
-1
group VIIIA loses/gains __________ electrons.
0
they are noble elements
Elements with high ionization energies are __________ reactive.
less
Elements with low ionization energies are_______ reactive
more
because they are more likely to lose electrons and form positive ions, because less energy is required to remove them from the valence shell.
why across a period shielding effect remain constant?
the number of inner electrons shielding the outer electrons remains the same.
the more shielding effect the less ionization energy. T/F
true
high ionization energy, _______ attraction to the nucleus
stronger
low ionization energy ,_______ attraction to the nucleus
lower
greater shielding effect ________ ionization energy. why?
lower
across a period, the ionization energy ____________. why?
increases
increasing nuclear charge, which results in the outermost electron being more strongly bound to the nucleus.
along a group, the ionization energy __________. why?
decreases
cz a shell is added and electron is weakly attracted to the nucleus hence less energy is required and less ionization energy
If an atom has a high ionization energy, what can you infer about its reactivity?
It is unreactive and unlikely to form compounds.
When an atom has a higher ionization energy, it requires a lot energy to remove an electron, and the atom is stable and has a lower reactivity.
The ionization energy of an atom tends to __________ as the number of valence electrons decreases.
increase
As the number of valence electrons decreases, the remaining electrons are closer to the nucleus, experiencing a stronger attractive force. This increased attraction makes it more difficult to remove an electron, resulting in a higher ionization energy.
Non-metals tend to have __________ ionization energies compared to metals. why?
higher
non-metals have high electronegativities and small size so more energy is required to remove an electron.
the atomic radius increases, the ionization energy _________.
decreases
what is high electron affinity?
a higher electron affinity means that more energy is released when an electron is added to the atom.
high electron affinity= more -ve value of electron affinity
The more negative the electron affinity value, the higher an atom’s affinity for electrons.
lower electron affinity indicates _______________ why?
does not accepts electron easily
weaker attraction force b/w nucleus and electrons.
release less energy.
atoms with lower electron affinities are more/less likely to gain electrons.
why?
less
A lower (less negative) electron affinity indicates that less energy is released during this process, meaning that less attraction b/w the nucleus, so less likely to accept electrons because of lower attraction.
higher electron affinity indicates that an atom more/less easily accepts electrons.
why?
more easily accepts electrons.
cz high E. I indicate more attraction to the nucleus so the more attraction, the more easily it will accept electrons.
what is electron affinity?
the amount of energy released when an electron is added to its valance shell in an isolated gaseous atom
if an electron is away from the nucleus it has __________ electron affinity.
low
it’ll release less energy
electron less attracted to nucleus so weaker attraction to the nucleus so less energy is released so less electron affinity.
if an electron is near to the nucleus it has __________ electron affinity.
high
smaller atomic radius result in a stronger attraction for electrons, leading to higher electron affinity.
electron affinity __________ across a period.
increases.
decrease atomic size= increase atomic number
electron are near the nucleus
electron affinity ________ along a group.
decreases
increase atomic size = more shells are added
electrons are far from the nucleus.
when an electron is strongly attracted to the nucleus the more/less likely it’ll be able gain electron.
more
electron affinity
The stronger the attraction to the nucleus, the more/less energy will be released. why?
more
the more energy is released when an electron is added to the atom, indicating a stronger attraction between the added electron and the nucleus.
electronegativity is directly/inversely proportional to the nuclear charge. why?
directly
nuclear charge (no. of protons) increases so E.N increases across a period.
electronegativity is directly/inversely proportional to the atomic radius. why?
inversely
atomic radius decreases E.N increases.
electronegativity _________ across a period. why?
increases
electronegativity _________ down a group. why?
decreases
the atomic size increases and shielding effect increases.
shielding effect depends on what factors?
The number of inner electrons.
state the periodic law?
When elements are arranged in order of increasing atomic number, there is a periodic repetition of their chemical and physical properties.
what is a periodic table?
a table showing systematic arrangement of elements.
how many elements in period 6?
32
same for 4 and 5
why IA & IIA group is called s-block elements?
cz their valence electrons lie in s-sub shell
3rd period has valence electron in _______ shell.
M shell
ionization energy depends on what factors? explain
Nuclear charge
Atomic radius
Shielding effect
electron affinity depends on what factors? explain
Nuclear charge
Atomic radius
Shielding effect
electronic configuration
electronegativity depends on what factors? explain
Nuclear charge
Atomic radius
Shielding effect
atomic size depends on what factors? explain
Nuclear charge
Shielding effect
Number of shells
what is electronegativity?
the amount of energy released when an electron adds up in the valence shell of an isolated gaseous atom to form a uninegative gaseous ion.
electronegativity always happens in a single atom or bonded atom?
bonded
chemical bond
typically covalent bonds
electronegativity ______________
across a period. why?
increases
increase in nuclear charge, decrease in atomic radius.
