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ra1l [238]
3 years ago
15

Two representative elements are in the same period of the periodic table. Which statement correctly describes the atoms of the t

wo elements?(1 point)
They have the same number of valence electrons.
They have the same number of valence electrons.

They have valence electrons in different energy levels.
They have valence electrons in different energy levels.

They have valence electrons in the same energy level.
They have valence electrons in the same energy level.

They have the same number of electrons.Helium is in group 18 of the periodic table. How is helium different from the other elements in this group?(1 point)Helium atoms have valence electrons in the first energy level, while atoms of the other elements in the group have valence electrons in the second energy level.
Helium atoms have valence electrons in the first energy level, while atoms of the other elements in the group have valence electrons in the second energy level.

Helium atoms have 2 valence electrons, while atoms of the other elements in the group all have 8 valence electrons.
Helium atoms have 2 valence electrons, while atoms of the other elements in the group all have 8 valence electrons.

Helium atoms have a full outer energy level, while atoms of the other elements in the group do not have a full outer energy level.
Helium atoms have a full outer energy level, while atoms of the other elements in the group do not have a full outer energy level.

Helium atoms have 2 electrons, while atoms of the other elements in the group all have 18 electrons.
Use the periodic table to answer the question.
Which element has atoms with valence electrons in a higher energy level than those of calcium (Ca)?
lithium (Li)
lithium (Li)

cesium (Cs)


bromine (Br)

oxygen (O)
Use the periodic table to answer the question.
Which statement best describes the arrangement of electrons in an atom of fluorine (F)?
There are seven electrons in the first energy level and two electrons in the second energy level.
There are seven electrons in the first energy level and two electrons in the second energy level.

There are five electrons in the first energy level and two electrons in the second energy level.
There are five electrons in the first energy level and two electrons in the second energy level.

There are two electrons in the first energy level and seven electrons in the second energy level.
There are two electrons in the first energy level and seven electrons in the second energy level.

There are two electrons in the first energy level and five electrons in the second energy level.
Physics
1 answer:
oksian1 [2.3K]3 years ago
7 0

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.

Learn more at brainly.com/question/24373385

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ListenA person on a ledge throws a ball vertically downward, striking the ground below the ledge with 200 joules of kinetic ener
polet [3.4K]

Answer:

A. 200 J

Explanation:

The initial kinetic energy depends on the initial speed, while the gravitational potential energy depends on the height, both balls are thrown with the same initial speed and from the same height. Therefore, due to the law of conservation of energy, the balls must have the same mechanical energy (the sum of both energies) when both impact the ground. Since the potential energy is zero at this point, its final kinetic energy must also be the same.

8 0
3 years ago
20.0 -kg cannonball is fired from a cannon with muzzle speed of 1000m/s at an angle of 37.0° with the horizontal. A second ball
Dovator [93]

The mechanical energy for the first and the second ball is

10 ^{7}  \: joules.

Mass of the first ball = 20 kg

The initial speed at which a cannonball is fired from a cannon =1000 m/s

The angle made by the cannonball while being fired from the cannon = 37°

The maximum height reached by the first ball is,

=   \frac{ u {}^{2} _{1}sin {}^{2} θ}{2g}

=    \frac{ {1000}^{2} sin {}^{2}37°}{2 \times 9.8}

= 18478.69 \: m

The maximum height of the first cannonball is 17478.69 m.

The initial speed at which a cannonball is fired from a cannon =1000 m/s

The angle made by the cannonball while being fired from the cannon = 90 °

=   \frac{ u {}^{2} _{2}sin {}^{2} θ}{2g}

=   \frac{ 1000{}^{2}sin^{2} 90°}{2 \times 9.8}[tex] = 51020.41 \: m

For the first ball, total mechanical energy= Potential energy at maximum height + kinetic energy at the maximum height

So, the total mechanical energy is,

= mgh \: + \frac{1}{2}mv {}^{2} _{x}[/tex]

= 20 \times 9.8 \times 18478.64  \times  \frac{20}{2} (1000 \: cos37 °)

= 10 ^{7}  The potential energy at the maximum height, = m _{2}gh

= 20 \times 9.8  \times 51020.41

= 10 ^{7} \:J

Therefore, the total mechanical energy for the first and the

\:second \:  cannonball \:  is  \: 10 ^{7}  \:joules.

To know about energy, refer to the below link:

brainly.com/question/1932868

#SPJ4

5 0
2 years ago
1. A sprinter races in the 100 meter dash. It takes him 10 second to reach the finish line
poizon [28]

Answer:

v = 10 m/s

Explanation:

Given that,

Distance covered by a sprinter, d = 100 m

Time taken by him to reach the finish line, t = 10 s

We need to find his average velocity. We know that velocity is equal to the distance covered divided by time taken. So,

v = d/t

v=\dfrac{100\ m}{10\ s}\\\\v=10\ m/s

Hence, his average velocity is 10 m/s.

6 0
3 years ago
what is the answer for the path that one body in space takes as it revolves around another body is called a .......... a orbit,a
salantis [7]
The answer is orbit, we are orbiting the sun as the moon orbits us
6 0
3 years ago
The specific heat of a certain type of metal is 0.128 J/(g⋅∘C).0.128 J/(g⋅∘C). What is the final temperature if 305 J305 J of he
Makovka662 [10]

Answer:

45.3°C

Explanation:

Heat gained = mass × specific heat × increase in temperature

q = mC (T − T₀)

Given C = 0.128 J/g/°C, m = 94.0 g, q = 305 J, and T₀ = 20.0°C:

305 J = (94.0 g) (0.128 J/g/°C) (T − 20.0°C)

T = 45.3°C

6 0
3 years ago
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