Answer:
B.
Explanation:
(1) Rb (3) Si
(2) Rn (4) Sr
Element which has both metallic and non-metallic properties is silicon as it is a metalloid.
Metalloids are defined as the elements which possess properties of both metals as well as non-metals.These elements are present only in the p-block of the periodic table.
In the p-block of the periodic table, these are the elements which separate the metals from the non metals by forming a zig-zag line between them.
These elements have 4 electrons in their valence shell which indicates that they can neither loose nor accept electrons rather share them between the 2 atoms.
As the elements are present between metals and non-metals they resemble both categories of elements in terms of their properties.They usually possess metallic appearances but are brittle.
Chemically, the behave as non-metals and have a characteristic property of forming alloys.They can form amphoteric or weakly acidic oxides.
Learn more about metalloids,here:
#SPJ5
The correct answer is option 2. One way of expressing concentration is by expressing it by parts per million or ppm. It is calculated by dividing the grams of solute and the grams of the solution, and the result is multiplied by 1 000 000. Parts per million is equal to 1 milligram of solute per kilogram of solution.
Answer:
In polar coordinates, the origin is called the pole.
Explanation:
The position of a point in a polar coordinate system is defined by using the distance from a fixed point and an angle made with a fixed ray from that point. It is a two-dimensional coordinate system.
The polar coordinates is defined as
Where, r is radius and θ is the angle with the polar axis, i.e. positive axis.
In a coordinate system (0,0) is called origin.
In polar coordinate system (0,0) is called pole.
Therefore, in polar coordinates, the origin is called the pole.
B. 1 kiloparsec
C. 1 light-year
D. 1 AU
The distance between the Earth and the Sun is approximately 1 AU (Astronomical Unit). Therefore, option D is correct.
One AU is defined as the average distance between the Earth and the Sun, which is about 93 million miles (150 million kilometers). It is a convenient unit of measurement for distances within our solar system.
A parsec is a unit of distance used for objects outside our solar system, equal to approximately 3.26 light-years. One kiloparsec is equal to 1,000 parsecs, or approximately 3,260 light-years. Therefore, neither A nor B is the correct answer.
A light-year is the distance that light travels in one year, which is approximately 5.88 trillion miles (9.46 trillion kilometers). Therefore, C is also not the correct, as the distance between the Earth and the Sun is much less than one light-year.
Therefore, the correct answer is D. 1 AU
Find more on astronomical unit :
#SPJ3