Answer:
Below are the statements which are true about the structure of the periodic table:
B: The inner transition elements are placed at the bottom of the periodic table for easy viewing.
D: The distribution of electrons in energy levels is responsible for the shape of the periodic table.
Explanation:
Point A:
As we know that in a periodic table there are 7 period s and 18 groups. So, the number of periods is evidently lesser than the number of groups. But the shape of periodic table is regular and rectangular so point A is false.
Point B:
The inner transition elements or -f block elements are put at the bottom for easy viewing. These are the elements that have the valence electrons only in the f-orbital's. Therefore, they are placed separately at the bottom side of the table so that they can be easily viewed or studied from there. So, point B is true.
Point C:
If we talk about option C, then it is very clear and true that considering a rectangular shape of the periodic table, the groups are vertically arranged and periods are horizontally arranged, therefore it is false.
Point D:
Atoms of all elements have definite electronic distribution in different energy levels like s, p d or f. This is a very prominent feature of periodic tale that elements are divided in specific blocks, s, p, d and f based on their electronic configurations. Therefore, it is true.
Point E:
We also know that no. of metals in a periodic table are more than the no. of non metals like almost 91 out of 118 elements are metals in periodic table. Therefore, the point E "Nonmetals take up more than half the area of the periodic table." is false.
Hope it helps!
The correct answer from the choices given is the third option. Covalent compounds have low boiling points. Also, their melting points are low. Covalent bonds have relatively low attractions which results to these properties. The bonds are easily broken by taking energy or adding energy.
It is possible to rate your active reading skills either by using a number is a specific rate or by using a word that qualifies your performance.
<h3>What are active reading skills?</h3>
Active reading skills are a set of skills that help you read actively; this means skills to effectively read a text and understand it.
<h3>How to rate your reading skills?</h3>
In this case, you are asked to rate your ability to pay attention to your understanding, thoughts, and questions while reading. To do this you can:
Rate using numbers:
- Select a specific scale rating such as 1 to 5 or 1 10.
- Analyze honestly if you used this ability while reading the text.
- Give yourself a number. For example, if you apply this skill only sometimes while reading you can rate yourself 5 out of 10.
Rate using words:
- Select the types of words that you will use, the most common ones are frequency words such as always, sometimes, and never.
- Analyze honestly your performance.
- Find the word that best fits it.
Learn more about rate in: brainly.com/question/2278897
Answer:
The melting point range of a substance is the temperature range from which the first crystal starts to melt, to the temperature at which the last crystal finishes melting. An impure substance is a type of mixture, so melting points can be used to find out if a substance is pure or impure.
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Explanation:
Answer:
Copper electrical wires are safer to use than wires made of most other conductive metals because they are resistant to heat. As you can see, copper is the preferred metal for electrical wires for several reasons. It has high electrical conductive; it's inexpensive; it's ductile; and it's thermal resistant.
