Fill in the blanks.
1. The symbol for potassium (K) is taken from its Latin name
(Cuprum/Kalium).
(Formula/Symbol) means a short form of representing something.
(Cu/Co) is the symbol used to represent the element cobalt.
... (element/compound) is a pure substance made up of two or more elements
combined in a fixed proportion.
5. The electrons present in the outermost shell of an atom are called
(radical/valence)
electrons.
6. Most of the metallic ions carry
(positive/negative) charge.
Answers
Answer:
1.kalium.
2.symbol.
3.cobalt.
4.compound.
5.valence.
6.positive.
Answer:
Potassium metal reacts rapidly with atmospheric oxygen to form flaky white potassium peroxide in only seconds of exposure. It was first isolated from potash, the ashes of plants, from which its name derives. In the periodic table, potassium is one of the alkali metals, all of which have a single valence electron in the outer electron shell, that is easily removed to create an ion with a positive charge – a cation, that combines with anions to form salts. Potassium in nature occurs only in ionic salts. Elemental potassium reacts vigorously with water, generating sufficient heat to ignite hydrogen emitted in the reaction, and burning with a lilac-colored flame. It is found dissolved in sea water (which is 0.04% potassium by weight[6][7]), and occurs in many minerals such as orthoclase, a common constituent of granites and other igneous rocks.
Potassium, 19K
Potassium-2.jpg
Potassium pearls (in paraffin oil, ~5 mm each)
Potassium
Pronunciation
/pəˈtæsiəm/ (pə-TAS-ee-əm)
Appearance
silvery gray
Standard atomic weight Ar, std(K)
39.0983(1)[1]
Potassium in the periodic table
Hydrogen
Helium
Lithium
Beryllium
Boron
Carbon
Nitrogen
Oxygen
Fluorine
Neon
Sodium
Magnesium
Aluminium
Silicon
Phosphorus
Sulfur
Chlorine
Argon
Potassium
Calcium
Scandium
Titanium
Vanadium
Chromium
Manganese
Iron
Cobalt
Nickel
Copper
Zinc
Gallium
Germanium
Arsenic
Selenium
Bromine
Krypton
Rubidium
Strontium
Yttrium
Zirconium
Niobium
Molybdenum
Technetium
Ruthenium
Rhodium
Palladium
Silver
Cadmium
Indium
Tin
Antimony
Tellurium
Iodine
Xenon
Caesium
Barium
Lanthanum
Cerium
Praseodymium
Neodymium
Promethium
Samarium
Europium
Gadolinium
Terbium
Dysprosium
Holmium
Erbium
Thulium
Ytterbium
Lutetium
Hafnium
Tantalum
Tungsten
Rhenium
Osmium
Iridium
Platinum
Gold
Mercury (element)
Thallium
Lead
Bismuth
Polonium
Astatine
Radon
Fran
↑
K
↓
Rb
argon ← potassium → calcium
Atomic number (Z)
19
Group
group 1: H and alkali metals
Period
period 4
Block
s-block
Element category
Alkali metal
Electron configuration
[Ar] 4s1
Electrons per shell
2, 8, 8, 1
Physical properties
Phase at STP
solid
Melting point
336.7 K (63.5 °C, 146.3 °F)
Boiling point
1032 K (759 °C, 1398 °F)
Density (near r.t.)
0.89 g/cm3
when liquid (at m.p.)
0.828 g/cm3
Critical point
2223 K, 16 MPa[2]
Heat of fusion
2.33 kJ/mol
Heat of vaporization
76.9 kJ/mol
Molar heat capacity
29.6 J/(mol·K)
Atomic properties
Oxidation states
−1, +1 (a strongly basic oxide)
Electronegativity
Pauling scale: 0.82
Ionization energies
1st: 418.8 kJ/mol
2nd: 3052 kJ/mol
3rd: 4420 kJ/mol
(more)
Atomic radius
empirical: 227 pm
Covalent radius
203±12 pm
Van der Waals radius
275 pm
Color lines in a spectral range
Spectral lines of potassium
Other properties
Natural occurrence
primordial
Crystal structure
body-centered cubic (bcc)Body-centered cubic crystal structure for potassium
Speed of sound thin rod
2000 m/s (at 20 °C)
Thermal expansion
83.3 µm/(m·K) (at 25 °C)
Thermal conductivity
102.5 W/(m·K)
Electrical resistivity
72 nΩ·m (at 20 °C)
Magnetic ordering
paramagnetic[3]
Magnetic susceptibility
+20.8·10−6 cm3/mol (298 K)[4]
Young's modulus
3.53 GPa
Shear modulus
1.3 GPa
Bulk modulus
3.1 GPa
Mohs hardness
0.4
Brinell hardness
0.363 MPa
CAS Number
7440-09-7
History
Discovery and first isolation
Humphry Davy (1807)
Main isotopes of potassium
Isotope Abundance Half-life (t1/2) Decay mode Product
39K 93.258% stable
40K 0.012% 1.248×109 y β− 40Ca
ε 40Ar
β+ 40Ar
41K 6.730% stable
Category Category: Potassium
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Potassium is chemically very similar to sodium, the previous element in group 1 of the periodic table. They have a similar first ionization energy, which allows for each atom to give up its sole outer electron. It was suspected in 1702 that they were distinct elements that combine with the same anions to make similar salts,[8] and was proven in 1807 using electrolysis. Naturally occurring potassium is composed of three isotopes, of which 40
K is radioactive. Traces of 40
K are found in all potassium, and it is the most common radioisotope in the human body.
Potassium ions are vital for the functioning of all living cells. The transfer of potassium ions across nerve cell membranes is necessary for normal nerve transmission; potassium deficiency and excess can each result in numerous signs and symptoms, including an abnormal heart rhythm and various electrocardiographic abnormalities. Fresh fruits and vegetables are good dietary sources of potassium. The body responds to the influx of dietary potassium, which raises serum potassium levels, with a shift of potassium from outside to inside cells and an increase in potassium excretion by the kidneys.
Most industrial applications of potassium exploit the high solubility in water of potassium compounds, such as potassium soaps. Heavy crop production rapidly depletes the soil of potassium, and this can be remedied with agricultural fertilizers containing potassium, accounting for 95% of global potassium chemical production.[9]