Question

Iestions
1. Name the three sub-atomic
particles of an atom.
Helium atom has an atomic mass
of 4 u and two protons in its
nucleus. How many neutrons
does it have?​

Answer 1

Answer:

1. the three sub atomic particles of atom are protons,electrons and neutrons..

2.we know that atomic mass=no of protons +no of neutrons.so,4u=2+x

therefore no of neutrons is 2...

hope it will help!

Answer 2

$\huge\mathfrak\red{ϙᴜᴇsᴛɪᴏɴ}$

ɴᴀᴍᴇ ᴛʜᴇ ᴛʜʀᴇᴇ sᴜʙ-ᴀᴛᴏᴍɪᴄ ᴘᴀʀᴛɪᴄʟᴇs ᴏғ ᴀɴ ᴀᴛᴏᴍ.

$\huge\mathfrak\green{ᴀɴsᴡᴇʀ}$

ᴀɴ ᴀᴛᴏᴍ ᴄᴏɴsɪsᴛs ᴏғ ᴛʜʀᴇᴇ sᴜʙᴀᴛᴏᴍɪᴄ ᴘᴀʀᴛɪᴄʟᴇs:

• ᴘʀᴏᴛᴏɴs – ᴘᴏsɪᴛɪᴠᴇʟʏ ᴄʜᴀʀɢᴇᴅ
• ᴇʟᴇᴄᴛʀᴏɴs – ɴᴇɢᴀᴛɪᴠᴇʟʏ ᴄʜᴀʀɢᴇᴅ
• ɴᴇᴜᴛʀᴏɴs – ɴᴇᴜᴛʀᴀʟ ɪɴ ɴᴀᴛᴜʀᴇ

$\huge\mathfrak\red{ϙᴜᴇsᴛɪᴏɴ}$

ʜᴇʟɪᴜᴍ ᴀᴛᴏᴍ ʜᴀs ᴀɴ ᴀᴛᴏᴍɪᴄ ᴍᴀss ᴏғ 4 ᴜ ᴀɴᴅ ᴛᴡᴏ ᴘʀᴏᴛᴏɴs ɪɴ ɪᴛs ɴᴜᴄʟᴇᴜs. ʜᴏᴡ ᴍᴀɴʏ ɴᴇᴜᴛʀᴏɴs ᴅᴏᴇs ɪᴛ ʜᴀᴠᴇ?

$\huge\mathfrak\green{ᴀɴsᴡᴇʀ}$

ɢɪᴠᴇɴ:

ᴀᴛᴏᴍɪᴄ ᴍᴀss ᴏғ ʜᴇʟɪᴜᴍ ᴀᴛᴏᴍ = $4$u, $2$ ᴘʀᴏᴛᴏɴs ɪɴ ʜᴇʟɪᴜᴍ ɴᴜᴄʟᴇᴜs

ᴀᴛᴏᴍɪᴄ ᴍᴀss = ɴᴜᴍʙᴇʀ ᴏғ ᴘʀᴏᴛᴏɴs + ɴᴜᴍʙᴇʀ ᴏғ ɴᴇᴜᴛʀᴏɴs

$4 = 2$ + ɴᴜᴍʙᴇʀ ᴏғ ɴᴇᴜᴛʀᴏɴs

ɴᴜᴍʙᴇʀ ᴏғ ɴᴇᴜᴛʀᴏɴs = $4 – 2 = 2$

ʜᴇɴᴄᴇ, ʜᴇʟɪᴜᴍ ʜᴀs $2$ ɴᴇᴜᴛʀᴏɴs.