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Each row in the table contains elements that have the same number of electron orbit shells. The first orbit, which is closest to the nucleus only has space for 2 electrons (no idea why, sorry). This is why only hydrogen (1 electron) and helium (2 electrons) are in the first row.
The second row has the same inner shell, with 2 electrons and an outer shell with room for 8...and so on.
What else can I help you with?
The first period in the periodic table represents elements that possess only the first energy level s orbital therefore this period contains?
Two elements
From left to right across the second period of the periodic table?
The second period of the periodic table contains elements from lithium to neon, in increasing atomic number order. These elements have increasing numbers of protons and electrons as you move from left to right across the period, resulting in changes in properties such as atomic size and reactivity.
Period in chemistry?
A period is a horizontal row on the periodic table of the elements. There are seven periods on the periodic table. Each period corresponds to the highest energy level that contains electrons. For example, the elements in the first period have electrons in the first energy level, which is the only energy level available; the elements in the second period have their highest energy electrons in the second energy level; the elements in the third period have their highest energy electrons in the third energy level, and so on.
How many elements in the first period?
Period 1: 2 elements Period 2: 8 elements Period 3: 8 elements Period 4: 18 elements Period 5: 18 elements Period 6: 32 elements Period 7: 25 elements
What level is filled by krypton?
The fourth electron shell is filled by krypton. Krypton is the last element in the fourth period on the periodic table. Each of the periods represents an electron shell. Elements in the first period have electrons in the first shell; elements in the second period have electrons in the second shell; and so on.
The first period in the periodic table represents elements that possess only the first energy level s orbital therefore this period contains?
Two elements
How many elements occur in each of the first three periods or the periodic table?
There are 2 elements in the first period, 8, 8 elements in 2nd and 3rd periods respectively,
From left to right across the second period of the periodic table?
The second period of the periodic table contains elements from lithium to neon, in increasing atomic number order. These elements have increasing numbers of protons and electrons as you move from left to right across the period, resulting in changes in properties such as atomic size and reactivity.
The first period on the periodic table represents elements that possess only the first energy level s orbital therefore this period contains?
two
The first period in the peroidical table represents elements that possese elements only the first energy level is orbital thefore this perid contains?
two elements, hydrogen and helium.
Period in chemistry?
A period is a horizontal row on the periodic table of the elements. There are seven periods on the periodic table. Each period corresponds to the highest energy level that contains electrons. For example, the elements in the first period have electrons in the first energy level, which is the only energy level available; the elements in the second period have their highest energy electrons in the second energy level; the elements in the third period have their highest energy electrons in the third energy level, and so on.
How many elements in the first period?
Period 1: 2 elements Period 2: 8 elements Period 3: 8 elements Period 4: 18 elements Period 5: 18 elements Period 6: 32 elements Period 7: 25 elements
Which period table group are made up of only gases?
The first period or row contains only elements that are gases at standard temperature and pressure.
Since the first energy level contains only the 1s sublevel the number of elements in this period is?
The first period in the periodic table contains two elements: hydrogen and helium. Hydrogen has one electron in its 1s orbital, while helium has two electrons in its 1s orbital.
What elements belong to the first period?
There are two elements in the first period, hydrogen and helium.
Why is there no p block elements in the first period of the periodic table?
The first period of the periodic table can hold a maximum of 2 electrons, which are filled in the s orbital. There are no p orbitals in the first period, which is why there are no p-block elements in the first period. The p-orbital becomes available in the second period.
What level is filled by krypton?
The fourth electron shell is filled by krypton. Krypton is the last element in the fourth period on the periodic table. Each of the periods represents an electron shell. Elements in the first period have electrons in the first shell; elements in the second period have electrons in the second shell; and so on.
