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rodikova [14]
3 years ago
12

The first 18 elements in the periodic table have which of the following important properties? a. They have the largest atomic nu

mbers c. Most occur as liquids at room temperature b. They do not typically combine with other elements to form compounds d. These elements make up most of the matter of the known universe Please select the best answer from the choices provided A B C D
Chemistry
2 answers:
fenix001 [56]3 years ago
7 0
<span>d. These elements make up most of the matter of the known universe</span>
GalinKa [24]3 years ago
5 0
Its actually a and possibly d but more likely a if they are the first 18 elements

 
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When does a star reach equilibrium?
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Actually, that does not happen until the protostar becomes a star when nuclear ignition starts and is maintained. It takes awhile for new star to go through its T-Tauri stage and settle down on the main sequence. 

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3 years ago
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What are the 6 things needed on a graph?
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1. Always give your graph a title in the following form: "The dependence of (your dependent variable) on (your independent variable). <span><span>Let's say that you're doing a graph where you're studying the effect of temperature on the speed of a reaction. In this reaction, you're changing the temperature to known values, so the temperature is your independent variable. Because you don't know the speed of the reaction and speed depends on the temperature, the speed of the reaction is your dependent variable. As a result, the title of your graph will be "The dependence of reaction rate on temperature", or something like that.</span> 

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3 years ago
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Identify the neutral element represented by this excited-state electron configuration, then write the ground-state electron conf
sineoko [7]

Answer:

1s² 2s² 2p³

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Explanation:

Excited state configuration: 1s² 2s² 2p² 3s¹

Unknown:

Ground state configuration = ?

Element symbol = ?

Solution:

Let us start by understanding what a ground state configuration entails:

A ground state configuration shows the lowest allowed energy levels of an atom. The excited state denotes when electrons have moved to higher energy levels away from their ground state.

The superscript in the configuration depicts the number of electrons in each of the sublevels.

We can use this number to identify the atom we are dealing with:

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The element with 7 electrons on the periodic table is Nitrogen.

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In writing the electronic configuration of an atom, certain rules must be complied with.

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To fill the s-orbital = 2 electrons

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The outermost shell electrons are usually the ones excited.

  Now, the 3s¹ shell is an excited one taking 1 electron from the second energy level;

 The ground state configuration is 1s² 2s² 2p³

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3 years ago
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omeli [17]

Answer:

A

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Solid
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