Elements in the periodic table are arranged in the increasing order of their atomic number.
An atom will contain equal amount of protons and electrons. If two elements are in same period of periodic table then these elements will have same number of electrons.
Helium is one of the seven elements which are called as noble gases. This gas is odorless, tasteless and colorless which makes it unique from other elements.
It has two valence electrons while atoms of other elements in the group have 8 valence electrons.
Lithium has one valence electron, while calcium atom has 2 valence electrons.
The highest level of energy is due valence electrons of an atom. The correct answer is Lithium.
Fluorine element has 9 electrons. There are 2 electrons in the first energy level and seven electrons in the second energy level.
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Answer:
After sufficient thickness of ice is formed it prevents further loss of heat from the bottom layers of water. This is why fishes and other aquatic animals and plants can survive in ponds and other water bodies even when the atmospheric temperature reaches or is well below 0 degrees.The anomalous expansion of water helps preserve aquatic life during very cold weather. When temperature falls, the top layer of water in a pond contracts becomes denser and sinks to the bottom. ... Thus, even though the upper layer are frozen, the water near the bottom is at 4°C and the fishes can survive in it easily.
Answer:
-2200 N
Explanation:
The change in momentum of Sarah is equal to the impulse, which is the product between the force exerted by the seatbelt on Sarah and the time during which the force is applied:
where
m is the mass
is the change in velocity
F is the average force
is the duration of the collision
In this problem:, we have:
m = 55 kg is Sarah's mass
is the change in velocity
is the duration of the collision
Solving for F, we find the force exerted by the seatbelt on Sarah:
Where the negative sign indicates that the direction of the force is opposite to that of Sarah's initial velocity.
The cooling on earth's surface (extrusive) makes a molten rock to become glassy. The lava cools so fast that crystals don't have time to form, which makes it glassy. Hope this helps!
Answer:
The focal length of the lens is 34.047 cm
The power of the needed corrective lens is 2.937 diopter.
Explanation:
Distance of the object from the lens,u = 26 cm
Distance of the image from the lens ,v= -110 cm
(Image is forming on the other side of the lens)
Since ,lens of the human eye is converging lens,convex lens.
Using a lens formula:
f = 34.047 cm = 0.3404 m
Power of the lens = P
