NTSE Level Test: Metals & Non-metals - Class 10

Bromine is the only non-metal at room temperature because the intermolecular forces are strong enough so that it does not vaporize at room temperature.

Nonmetals tend to form anions. With one, two, or three valence electrons metals tend to lose electrons to achieve a noble gas configuration. (It would require more energy to gain the 5 – 7 electrons needed to fill their valence shell.)

Explanation:
The least conductor of heat among the given options is lead. Here's why:
Conductivity of Heat:
Conductivity of heat refers to the ability of a material to conduct heat. Materials with high thermal conductivity allow heat to flow through them easily, while materials with low thermal conductivity resist the flow of heat.
Comparing the Options:
Let's compare the given options to determine the least conductor of heat:
- Gold: Gold is known for its high thermal conductivity, making it an excellent conductor of heat.
- Platinum: Platinum also has a high thermal conductivity, similar to gold.
- Silver: Silver is one of the best conductors of heat, even better than gold and platinum.
- Lead: Lead has a relatively low thermal conductivity compared to the other options. It is a poor conductor of heat.
Conclusion:
Based on the comparison, we can conclude that the least conductor of heat among the given options is lead (option D). It has a lower thermal conductivity compared to gold, platinum, and silver.

Which metal can we cut with a knife?

• Gold: Gold is a very soft metal and is easily deformed. It is not possible to cut gold with a knife.


• Potassium: Potassium is a highly reactive metal and reacts violently with water. It is not feasible to cut potassium with a knife.


• Iron: Iron is a relatively hard metal, but it can be cut with a knife. However, it may require a significant amount of force and may dull the knife in the process.


• All of these: The correct answer is not "All of these" because gold and potassium cannot be cut with a knife.

Therefore, the correct answer is B: Potassium.

Metals have 1-3 electrons in their outermost orbit. They are present on the extreme left of the periodic table. They tend to donate electrons and obtain the stable electronic configuration of the nearest noble gas. The valency on metals also ranges from 1-3 .

Neutral oxides show neither basic nor acidic properties and hence do not form salts when reacted with acids or bases, eg., water H2O,  carbon monoxide CO  etc. are neutral oxides. 

Calcium hydride is called hydrolith because C_aH₂ is a saline hydride,meaning that its structure is salt-like.

Answer:
The metalloid elements are those that have properties of both metals and nonmetals. They are located along the zigzag line on the periodic table. Among the options given, the metalloid element is:
A: Si (Silicon)
- Silicon is a metalloid element.
- It is a solid at room temperature.
- It has a shiny luster like metals.
- It is a good conductor of electricity like metals.
- However, it is brittle and semiconductor in nature like nonmetals.
- It is commonly used in the production of computer chips and solar cells.
B: Sb (Antimony)
- Antimony is not a metalloid element.
- It is a metallic element.
- It is a solid at room temperature.
- It has a metallic luster and is a good conductor of electricity.
D: Zn (Zinc)
- Zinc is not a metalloid element.
- It is a metallic element.
- It is a solid at room temperature.
- It has a metallic luster and is a good conductor of electricity.
Therefore, the correct answer is C: A and B (Si and Sb) as both Silicon and Antimony are metalloid elements.

The metal that does not react with oxygen is Au (Gold).

The detailed explanation is as follows:

• Cu (Copper): Copper reacts with oxygen in the air to form copper oxide. This can be seen as the greenish color on the surface of copper objects.


• Au (Gold): Gold is a noble metal and does not react with oxygen under normal conditions. It is highly resistant to corrosion and oxidation.


• A and B: This option includes both copper and gold. Since copper reacts with oxygen and gold does not, this option is incorrect.


• Fe (Iron): Iron readily reacts with oxygen to form iron oxide, commonly known as rust. This is why iron objects can rust when exposed to moisture and air.

Therefore, the correct answer is option B: Au (Gold).

Iron neither reacts with cold water nor with hot water but reacts with steam to produce hydrogen gas.

Silicon is doped with other Microelements to increase its conductivity. It is used in transistors, solar cells, semiconductor devices.

Of all metals in pure form, tungsten has the highest melting point (3,422 °C, 6,192 °F).

China Clay is also known as kaolin & white clay. Primary clay formed by natural kaolinisation process. it is formed by decomposition of some part of feldspar mineral.White in color , Used in ceramic slip casting process, Pressing processes and forming process as a body former and filler.

An alloy is a mixture of metals or a mixture of a metal and another element.
Explanation:
- An alloy is formed when two or more metals are mixed together. It can also be a mixture of a metal and another element.
- Alloys are created to improve the properties of the original metals, such as strength, durability, and resistance to corrosion.
- Common examples of alloys include bronze (copper and tin), steel (iron and carbon), and brass (copper and zinc).
- Alloys can have a wide range of compositions and properties, depending on the specific metals or elements involved.
- The different metals in an alloy are typically evenly distributed throughout the mixture, resulting in a homogeneous material.
- Alloys can be created through various methods, including melting and mixing the metals together, or by depositing one metal onto another through processes like electroplating.
- The properties of an alloy can be different from those of its constituent metals, making it a distinct material with unique characteristics.
- Alloys are widely used in various industries, including construction, automotive, aerospace, and electronics, due to their desirable properties and versatility.

Sulfuric acid is commonly supplied at concentrations of 78, 93 or 98 percent. Sulphuric acid is sometimes referred to as the " King of chemicals " because it is produced. 

Key Points:
- The non-metal that is the best conductor of electricity is graphite.
- Graphite is a form of carbon that has a unique structure allowing it to conduct electricity.
- This is due to the presence of delocalized electrons in its structure.
- Delocalized electrons are free to move throughout the material, allowing for the flow of electric current.
- Graphite is commonly used as an electrode material in batteries and fuel cells.
- It is also used in electrical contacts, such as in switches and relays.
- Other non-metals, such as phosphorus, fluorine, and bromine, are not good conductors of electricity.
- Phosphorus is a poor conductor because it is a non-metal and does not have delocalized electrons.
- Fluorine is a non-metal with a very high electronegativity, making it highly reactive and unlikely to conduct electricity.
- Bromine, although it is a liquid at room temperature, is also a poor conductor of electricity due to its non-metallic properties.

Silver chloride, silver bromide (AgBr) and silver iodide (AgI) are the three silver "halide" compounds used in photography.

Sodium bicarbonate, also commonly known as baking soda, is commonly seen as a white, fine powder and has the chemical formula NaHCO₃. It has one sodium atom, one hydrogen atom, one carbon atom, and three oxygen atoms. It is a very useful chemical that is alkaline in nature.

Carnallite is an evaporite mineral a hydrated potassium magnesium chloride. It is variably colored yellow to white, reddish or blue. It occurs with a sequence of potassium and magnesium evaporite.

Sodium is stored under kerosene because of its high chemical reactivity with almost all of other elements (for example oxygen from air which oxidizes it instantly). Kerosene and mineral oil are the only chemicals that make the sodium inert.

The magnesium is used in Flash bulb, Grignard reagent, Electron - alloy. When magnesium burns, it makes very bright white light. Elektron is an alloy containing magnesium (90%) , zinc, aluminum (9%) and other  other Metals (1%) .

M + O₂ -- MO₂ (super oxide)

Metal that has tendency to form super oxide : K (Potassium due to its large size)

With lithium, it forms lithium oxide. With sodium, it forms peroxide and oxide of sodium. With barium, it forms barium oxide.

The most malleable metal is Gold (Au).It must be surprising as most of us have never come across gold foils or gold leaf that often in our lives unlike aluminium,iron,copper foils.One reason for this must be because of the cost of this noble metal,gold.

Cinnabar is a toxic mercury sulfide mineral with a chemical composition of HgS. It is the only important ore of mercury. It has a bright red color that has caused people to use it as a pigment, and carve it into jewelry and ornaments for thousands of years in many parts of the world. Because it is toxic, its pigment and jewelry uses have almost been discontinued.

Iron is an essential element for blood production. About 70 percent of your body's iron is found in the red blood cells of your blood called hameoglobin.