All categories

2 years ago

How do you identify the number of valence electrons in an element using periodic table

2 answers:

5 0

You may look at what group they are in
Group
1A=Group 1
2A = Group 2
3A = Group 13
4A= Group 14
5A=Group 15
6A=Group 16
7A=Group 17

The #A tells you how many valence electrons there are by the # before A. Such as Chlorine, which is in 7A, so therefore has 7 valence electrons.

Fittoniya [83]2 years ago

4 0

Answer:

Sample Response: All elements in the same group of the periodic table have the same number of valence electrons. This made it possible to compare the valence of the alien elements to the valence of elements from our periodic table, and match the alien elements to the correct group. For example, our group 14 elements all have 4 valence electrons, so the alien element with 4 valence electrons had to be part of group 14 also.

Explanation:

You might be interested in

Between which two points of a concave mirror should an object be placed to obtain a magnificati of -3

kobusy [5.1K]

Answer:

When object is placed between the focus (F) and pole (P) of a concave mirror, magnified and erect image of the object is formed on the back of the mirror.

When object is placed between the centre of curvature and the principal focus of a concave mirror, magnified and inverted image is formed in front of the mirror.

Explanation:

8 0

2 years ago

What is the equivalent resistance between terminals A and B, measured in ohms?

Usimov [2.4K]

Answer:

c. 0.80

Explanation:

they will choose the path that has not resistance

8 0

2 years ago

The quartz crystal used in an electric watch vibrates with a frequency of 32,768 Hz. What is the period of the crystal's motion?

Elan Coil [88]

Answer:

Time period, $T=3.05\times 10^{-5}\ s$

Explanation:

Given that,

The quartz crystal used in an electric watch vibrates with a frequency of 32,768 Hz, f = 32768 Hz

We need to find the period of the crystal's motion. The relationship between the frequency and the time period is given by :

$T=\dfrac{1}{f}$

T is the time period of the crystal's motion.

Time period is given by :

$T=\dfrac{1}{32768}$

$T=3.05\times 10^{-5}\ s$

So, the time period of the crystal's motion is $3.05\times 10^{-5}\ s$ . Hence, this is the required solution.

8 0

3 years ago

You push very hard on a heavy desk, trying to move it. You do work on the desk:

frozen [14]

Answer:

Explanation:

We know that work done is given by

$W=F.d=Fdcos\Theta$

So there are two case in which work done is zero

First case is that when force and displacement are perpendicular to each other

And other case is that when there is no displacement

So for work to be done there must have displacement, if there is no displacement then there is no work done

So option (c) will be the correct option

3 0

2 years ago

A runner accelerated to 4 m/s^2 for 20 seconds before winning the race.How far did he/she run?

creativ13 [48]

Answer:

s=800 m

Explanation:

Given that,

Acceleration of a runner, a = 4 m/s²

Time, t = 20 seconds

We need to find the distance covered by her. Initially, she was at rest. It means its initial velocity is equal to 0. So, using second equation of motion as follows :

$s=ut+\dfrac{1}{2}at^2$

Herre, u = 0

$s=\dfrac{1}{2}at^2\\\\s=\dfrac{1}{2}\times 4\times (20)^2\\\\s=800\ m$

So, she will cover a distance of 800 m.

8 0

3 years ago