What type of light is emitted by electrons falling to the ground state?

J. Explain how an atom's valence electron configuration determines its place on the periodic table.

Darya [45]

Answer:

Elements having same valence electrons are placed in <u>same group.</u>

Explanation:

First, let's start with some basic concepts of modern periodic table:

1. Modern Periodic table : It is the arrangement of element in the increasing order of their atomic numbers

The Modern periodic table is divided into Periods and groups .

Periods : These are the horizontal rows. There are seven periods in the periodic table . Period 1 has 2 element. Period two and three has 8 elements , period 4 and 5 have 18 elements and the period 6 and 7 have 32 elements.

Same period have same number of atomic orbital(Shell)

Group : The group is the vertical columns . There are 18 groups in the modern periodic table.Those element which have same group number will also have same number of electron in their outermost shell. The number of electron in the outermost shell determines the valency of the element.

So, elements showing same valency are placed in same group.

All alkali are place in group 1 and have 1 valance electron in the outermost shell

5 0

4 years ago

The heat of fusion for a substance is 122 joules per gram. How many joules of heat are need to melt 7.50 grams of this substance

daser333 [38]

<h3>Answer:</h3>

915 Joules

<h3>Explanation:</h3>

The heat of fusion is the heat that is required to convert a given mass of a substance from solid state to liquid state without change in temperature.
In this case, we are given specific heat of a substance as 122 joules per gram
It means that amount of heat equivalent to 122 joules is required to change 1 gram of the substance from solid state to liquid state.

Therefore, we can determine the amount of heat needed to change 7.5 grams of the substance from solid to liquid state.

1 g = 122 Joules

7.5 g = ?

= 122 × 7.5

= 915 Joules

Thus, 7.5 g of the substance at its melting point will require 915 Joules of heat to melt.

4 0

3 years ago

A sphere has a mass of 64 g, and a density of 2.0 g/cm3 . what is the radius of the sphere

slega [8]

The size v=masse/density
v= 4*pi*R^3
R=(3*masse/(4*pi*density))^(1/3)
R=1.9695 cm

4 0

3 years ago

Hey ignore ths i didn mean to post

Sauron [17]

Answer:

WHYYYYYYYYYYYYYYYYYYYYYYY

Explanation:

you said you didnt mean to post it but still typed it and posted it LOLLLLLLLLLLLLLL

7 0

2 years ago

Urea (CH4N2O) is a common fertilizer that can be synthesized by the reaction of ammonia (NH3) with carbon dioxide as follows: 2N

Montano1993 [528]

The question is incomplete, here is the complete question:

Urea (CH₄N₂O) is a common fertilizer that can be synthesized by the reaction of ammonia (NH₃) with carbon dioxide as follows: 2NH₃(aq) + CO₂(aq) → CH₄N₂O(aq) + H₂O(l) In an industrial synthesis of urea, a chemist combines 135.9 kg of ammonia with 211.4 kg of carbon dioxide and obtains 178.0 kg of urea.

Determine the limiting reactant. (express your answer as a chemical formula)

<u>Answer:</u> The limiting reactant is ammonia $(NH_3)$