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kozerog [31]
3 years ago
13

In what era did dinasours first appear?

Chemistry
1 answer:
jenyasd209 [6]3 years ago
8 0

The answer is the Mesozoic Era


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etermine the number of valence electrons for each of the atoms. Enter each answer as a numeral. For example, if an atom has two
Sav [38]

Answer:

1. 1

2. 2

3. 6

4. 8

Explanation:

Valence electrons can be defined as the number of electrons present in the outermost shell of an atom. Valence electrons are used to determine whether an atom or group of elements found in a periodic table can bond with others. Thus, this property is typically used to determine the chemical properties of elements.

1. Li is the symbol for the chemical element known as Lithium: it has 1 valence electron. The electronic configuration of lithium is 1s²2s¹

2. Mg is the symbol for the chemical element known as Magnesium: it has 2 valence electrons. The electronic configuration of magnesium is 1s²2s²2p63s²

3. O is the symbol for the chemical element known as Oxygen: it has 6 valence electrons. The electronic configuration of magnesium is 1s²2s²2p⁴.

4. Ne is the symbol for the chemical element known as Neon: it has 8 valence electrons.

7 0
2 years ago
Recording a person’s fingerprints using ink or digital imaging is called a(n)____.
NNADVOKAT [17]
It is called a dactyloscopy
5 0
2 years ago
The first pesticides relied on natural chemicals, such as those taken from chrysanthemum flowers. is this true or false
Firdavs [7]
The first pesticides relied on natural chemicals, such as those taken from chrysanthemum flowers is true
4 0
3 years ago
Read 2 more answers
Helpppppppppppppp please
Mama L [17]
1)
-Lithium: Lithium got 3 protons, so it atomic number is 3. It is located on the first column of the periodic table, and belonging to the alkali metal. So lithium is a metal. Lithium is highly reactive.
-Neon: It is located on the 18th column of the periodic table, and belong to the noble gases. So Neon is a nonmetal. Neon's reactivity is very low.
-Fluorine: Located on the 17th column of the periodic metal, fluorine is a nonmetal, and belong to the halogen family. Fluorine's reactivity is high.

2)
-Vertical columns of the periodic table are called columns. There is 18 column in the periodic table, and each one represent a chemical family.
-Horizontal rows of the periodic table care called periods. There is 7 periods in the periodic table.
-The number of protons in an atom is that element's atomic number. And since the atom is electrically neutral, the number of protons is equal to the number of electrons. So if you have the number of electrons, you can still find the atomic number.
-The total of protons and neutrons in an atom is that element's atomic mass. Based on the formula A = Z + N, where A represents the atomic mass, Z the atomic number (number of protons) and N the number of neutrons.
-The elements in group 1 are the most reactive metals. This group is called the Alkali metals. They only have 1 electron in their outer shell which makes them always ready to lose an electron in an ionic bonding.
-The elements in group 17 are the most reactive nonmetals. This group is called the Halogens, with 7 electrons in their outer shell which makes them always ready to win an electron in an ionic bonding.
-The elements in group 18 are the most unreactive elements. This group is called the Noble gases. Their outer shell is always full, so it can't do reactions.

Hope this Helps! :)

4 0
3 years ago
What is the base dissociation constant for a weak base at equilibrium, B + H2O <===> BH+ + OH–?
podryga [215]
Depends on what the base is. You would reference the base dissociation chart for that value.
3 0
3 years ago
Read 2 more answers
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