Tabel
Tabel
Periodik
Periodik
Unsur
Unsur
Merupakan referensi kimiaSusunan unsur-unsur dengan informasi dasar
TABEL PERIODIK
• Dmitri Mendeleev, 1869: pengaturan unsur-unsur
yang diketahui dalam bentuk tabel periodik,
sebelum ada detail struktur atom.
– Berdasar: sifak fisik dan kimia unsur – Sifat kimia unsur meningkat secara periodik – Digolongkan berdasar massa atom
– Prediksi unknown elements: ada posisi kosong bila unsurnya tidak sesuai dgn yg diatas dan dibawah
– Saat unknown elements ditemukan, sifat-sifatnya mendekati yg diprediksi.
Tabel periodik
:
penyusunan unsur-unsur yang mana unsur-unsur
tersebut dipisahkan menjadi grup-grup berdasarkan
set pengulangan sifat-sifatnya.
-disusun berdasar kenaikan nomor atom
-terdiri dari deretan (periode) dan kolom (grup)
unsur-unsur
⇒
mempermudah dalam membandingkan sifat
unsur yg satu dengan yang lainnya.
• Hukum berkala: sifat-sifat kimia dan fisika unsur-unsur merupakan fungsi berkala dari nomor atomnya.
• Periodisitas kimia tidak berhubungan dengan massa atom, namun berhubungan dgn jumlah protonnya.
• Perilaku kimiawi unsur ditentukan oleh konfigurasi elektronnya • Tingkatan energi terkuantisasi sesuai lapisan elektron disekitar inti. • Tiap deretan (periode)diawali dgn kulit elektron terluar yang baru. – ditandai dengan kulit (n) sama⇒1 deretan dlm sistem periodik • Kolom dalam sistem periodik: grup, mengandung unsur-unsur yg
memiliki sifat kimia dan fisik yg serupa.
– diidentifikasi dari jumlah elektronnya pada kulit terluar, kecuali He
Periodisitas
• Menampilkan informasi:
• Nomor atom
• Simbol
• Massa atom
• Jumlah elektron valensi
• Wujud zat pd suhu kamar
Sifat Logam
•
Logam
: unsur-unsur yg umumnya padatan pada
suhu kamar. Paling banyak diantaranya adalah
logam.
•
Non-logam
: unsur-unsur pada pojok kanan atas
tabel periodik.
•
Metalloid
: unsur-unsur yang berada pada batas
diagonal antara logam dan non-logam. Sifat
kimia-fisiknya merupakan intermediet logam dan
non-logam.
Detail sifat2.
Alkali Metals
• The alkali family is found in the first column of the periodic table. • Atoms of the alkali metals have a single electron in their outermost level, in other words, 1 valence electron.
• They are shiny, have the consistency of clay, and are easily cut with a knife.
• They are the most reactive metals.
• They react violently with water.
• They are always bonded with another element.
Alkaline Earth Metals
• They are never found uncombined in nature.
• They have two valence electrons.
• Alkaline earth metals include magnesium
and calcium, among others.
Transition Metals
• Transition Elements include those elements in the B families. • These are the metals you are probably most familiar: copper, tin,
zinc, iron, nickel, gold, and silver.
• They are good conductors of heat and electricity. • The compounds of transition metals are usually brightly colored and are often used to color paints. • Transition elements have 1 or 2 valence electrons,
which they lose when they form bonds with other atoms. Some transition elements can lose electrons in their next-to-outermost level.
• Transition elements have properties similar to one another and to other metals, but their properties do not fit in with those of any other family.
• Many transition metals combine chemically with oxygen to
Boron Family
• The Boron Family is named
after the first element in the
family.
• Atoms in this family have 3
valence electrons.
• This family includes a
metalloid (boron), and the
rest are metals.
• This family includes the
most abundant metal in the
earth’s crust (aluminum).
Carbon Family
• Atoms of this family have 4
valence electrons.
• This family includes a
non-metal (carbon), non-metalloids, and
metals.
• The element carbon is called
the “basis of life.” There is an
entire branch of chemistry
devoted to carbon compounds
called organic chemistry.
Nitrogen Family
• The nitrogen family is named after the element that makes up 78% of our atmosphere. • This family includes
non-metals, metalloids, and metals. • Atoms in the nitrogen family
have 5 valence electrons. They tend to share electrons when they bond.
• Other elements in this family are phosphorus, arsenic, antimony, and bismuth.
Oxygen Family
• Atoms of this family have 6
valence electrons.
• Most elements in this family
share electrons when
forming compounds.
• Oxygen is the most
abundant element in the
earth’s crust. It is extremely
active and combines with
almost all elements.
Halogen Family
• The elements in this
family are fluorine,
chlorine, bromine,
iodine, and astatine.
• Halogens have 7 valence
electrons, which explains
why they are the most
active non-metals. They
are never found free in
nature.
Halogen atoms only need to gain 1 electron to fill their outermost energy level. They react with alkali metals to form salts.
Noble Gases
• Noble Gases are colorless gases that are extremely un-reactive. • One important property of the noble gases is their inactivity.
They are inactive because their outermost energy level is full. • Because they do not readily combine with other elements to
form compounds, the noble gases are called inert. • All have complete octets: stability.
• The family of noble gases includes helium, neon, argon, krypton, xenon, and radon.
• All the noble gases are found in small amounts in the earth's atmosphere.
Rare Earth Elements
• The thirty rare earth
elements are composed
of the lanthanide and
actinide series.
• One element of the
lanthanide series and
most of the elements in
the actinide series are
called trans-uranium,
which means synthetic
or man-made.
Atomic Radii Properties
Ionic Radii
The ionic radius of each ion is the portion of the distance between the nuclei occupied by that ion
Cationsare smaller than the atoms from which they are formed - the nucleus attractsthe remaining electrons more strongly
Anionsare larger than the atoms
from which they are formed - the greater number of electrons repelmore strongly
Ionization Energy
Ionization energyis the energy required to remove an electron
from a ground stateatom in the gaseous state
Electron Affinity
Electron affinityis the energy change that occurs when an electron is addedto a gaseous atom
Electron affinities are expressed as negative because the process is exothermic
A Summary of Periodic Trends
• Jumlah elektron valensi– Meningkat dalam 1 periode (kiri ke kanan) – Sama jika dalam satu gol.
• Ukuran atom
– Menurun dalam 1 periode – Meningkat dalam 1 gol. (atas ke bawah)
• Energi ionisasi
– Meningkat dalam 1 periode – Menurun dalam 1 gol.
• Afinitas elektron
– Meningkat dalam 1 periode – Menurun dalam 1 gol.
• Elektronegativitas
– Meningkat dalam 1 periode – Menurun dalam 1 gol.
• Ukuran ion
– Menurun dalam 1 periode – Meningkat dalam 1 gol.
• Sifat logam
– Menurun dalam 1 periode
R
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K
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ATOMIC STRUCTURE
ATOMIC STRUCTURE
the number of protons in an atom
the number of protons and neutrons in an atom
